Linux 68k 2000/Linux 68k 2000.iso/dokus/PCMCIA-HOWTO

Text File | 1997-11-15 | 88.6 KB | 1,895 lines

  Linux PCMCIA HOWTO
  David Hinds, [e-mail]
  v1.106, 14 November 1997

  This document describes how to install and use PCMCIA Card Services
  for Linux, and answers some frequently asked questions.  The latest
  version of this document can always be found at hyper.stanford.edu in
  /pub/pcmcia/doc.  An HTML version is at
  http://hyper.stanford.edu/HyperNews/get/pcmcia/home.html

  1.  General information and hardware requirements

  1.1.  Introduction

  Card Services for Linux is a complete PCMCIA support package.  It
  includes a set of loadable kernel modules that implement a version of
  the PCMCIA Card Services applications program interface, a set of
  client drivers for specific cards, and a card manager daemon that can
  respond to card insertion and removal events, loading and unloading
  drivers on demand.  It supports ``hot swapping'' of PCMCIA cards, so
  cards can be inserted and ejected at any time.

  This software is still under development.  It probably contains bugs,
  and should be used with caution.  I'll do my best to fix problems that
  are reported to me, but if you don't tell me, I may never know.  If
  you use this code, I hope you will send me your experiences, good or
  bad!

  If you have any suggestions for how this document could be improved,
  please let me know ([e-mail]).

  1.2.  Copyright notice and disclaimer

  Copyright (c) 1996, 1997 David A. Hinds

  This document may be reproduced or distributed in any form without my
  prior permission.  Modified versions of this document, including
  translations into other languages, may be freely distributed, provided
  that they are clearly identified as such, and this copyright is
  included intact.

  This document may be included in commercial distributions without my
  prior consent.  While it is not required, I would like to be informed
  of such usage.  If you intend to incorporate this document in a
  published work, please contact me to make sure you have the latest
  available version.

  This document is provided ``as is'', with no explicit or implied
  warranties.  Use the information in this document at your own risk.

  1.3.  What is the latest version, and where can I get it?

  The current major release of Card Services is version 2.9, and minor
  updates or bug fixes are numbered 2.9.1, 2.9.2, and so on.

  Source code for the latest version is available from
  hyper.stanford.edu in the /pub/pcmcia directory, as pcmcia-
  cs-2.9.?.tar.gz.  There will usually be several versions here.  I
  generally only keep the latest minor release for a given major
  release.  New major releases may contain relatively untested code, so
  I also keep the latest version of the previous major release as a
  relatively stable fallback; the current fallback is 2.8.23.  It is up
  to you to decide which version is more appropriate, but the CHANGES
  file will summarize the most important differences.
  hyper.stanford.edu is mirrored at sunsite.unc.edu in
  /pub/Linux/kernel/pcmcia.  I'll also try to upload major releases to
  tsx-11.mit.edu under /pub/linux/packages/laptops/pcmcia now and then.

  If you do not feel up to compiling the PCMCIA drivers from scratch,
  pre-compiled drivers are included with current releases of most of the
  major Linux distributions, including Slackware, Red Hat, Caldera, and
  Yggdrasil, among others.

  1.4.  What systems are supported?

  This code should run on almost any Linux-capable laptop.  All common
  PCMCIA controllers are supported, including Intel, Cirrus, Vadem,
  VLSI, Ricoh, and Databook chips.  Custom controllers used in IBM and
  Toshiba laptops are also supported.  PCMCIA card docks for desktop
  systems should work as long as they are the type that plugs directly
  into the ISA bus, rather than SCSI-to-PCMCIA or IDE-to-PCMCIA
  adapters.

  The Motorola 6AHC05GA controller used in some Hyundai laptops is not
  supported.  The custom PCMCIA controller in the HP Omnibook 600 is
  unsupported.  PCI to CardBus bridge controllers (from SMC, Ricoh,
  Cirrus, and TI) are currently supported only in legacy 16-bit mode,
  and this support is still somewhat experimental.

  1.5.  What PCMCIA cards are supported?

  The current release includes drivers for a variety of ethernet cards,
  a driver for modem and serial port cards, several SCSI adapter
  drivers, a driver for ATA/IDE drive cards, and memory card drivers
  that should support most SRAM cards and some flash cards.  The
  SUPPORTED.CARDS file included with each release of Card Services lists
  all cards that are known to work in at least one actual system.

  The likelihood that a card not on the supported list will work depends
  on the type of card.  Essentially all modems should work with the
  supplied driver.  Some network cards may work if they are OEM versions
  of supported cards.  Other types of IO cards (frame buffers, sound
  cards, etc) will not work until someone writes the appropriate
  drivers.

  1.6.  When will my new card be supported?

  Unfortunately, they usually don't pay me to write device drivers, so
  if you would like to have a driver for your favorite card, you are
  probably going to have to do at least some of the work.  Ideally, I'd
  like to work towards a model like the Linux kernel, where I would be
  responsible mainly for the ``core'' PCMCIA code and other authors
  would contribute and maintain drivers for specific cards.  The
  SUPPORTED.CARDS file mentions some cards for which driver work is
  currently in progress.  I will try to help where I can, but be warned
  that debugging kernel device drivers by email is not particularly
  effective.

  Manufacturers interested in helping provide Linux support for their
  products can contact me about consulting arrangements.

  1.7.  Mailing lists

  I used to maintain a database and mailing list of Linux PCMCIA users.
  More recently, I've turned my web page for Linux PCMCIA information
  into a ``HyperNews'' site, with a set of message lists for Linux
  PCMCIA issues.  There are lists for installation and configuration
  issues, for different types of cards, and for PCMCIA programming and
  debugging.  The Linux PCMCIA information page is at
  http://hyper.stanford.edu/HyperNews/get/pcmcia/home.html.  Users can
  request email notification of new responses to particular questions,
  or notification for all new messages in a given category.  I hope that
  this will become a useful repository of information, for questions
  that go beyond the scope of the HOWTO.

  There is a Linux mailing list devoted to laptop issues, the ``linux-
  laptop'' list.  For more information, send a message containing the
  word ``help'' to [e-mail].  To subscribe, send a
  message containing ``subscribe linux-laptop'' to the same address.
  This mailing list might be a good forum for discussion of Linux PCMCIA
  issues.

  The Linux Laptop Home Page at
  http://www.cs.utexas.edu/users/kharker/linux-laptop has links to many
  sites that have information about configuring specific types of
  laptops for Linux (and PCMCIA).  There is also a searchable database
  of system configuration information.

  2.  Compilation, installation, and configuration

  2.1.  Prerequisites and kernel setup

  Before starting, you should think about whether you really need to
  compile the PCMCIA package yourself.  All common Linux distributions
  come with pre-compiled PCMCIA driver packages.  Generally, you only
  need to install the drivers from scratch if you need a new feature of
  the current drivers, or if you've updated and/or reconfigured your
  kernel in a way that is incompatible with the drivers included with
  your Linux distribution.  While compiling the PCMCIA package is not
  technically difficult, it does require some general Linux familiarity.

  The following things should be installed on your system before you
  start installing PCMCIA:

  ╖  One of the following kernels: 1.2.8 through 1.2.13, 1.3.30, 1.3.37,
     1.3.39 through 1.3.99, 1.99.* (i.e., pre-2.0), 2.0.*, or 2.1.*.

  ╖  A current set of module utilities.

  ╖  (Optional) the ``Forms'' X11 user interface toolkit.

  The latest version requires a kernel version 1.2.8 or higher, or a
  development kernel 1.3.30 or higher.  1.3.38 is definitely broken, and
  1.3.31 to 1.3.36 are untested.  It also requires a relatively recent
  set of module utilities.  There are no kernel patches specifically for
  PCMCIA.

  You need to have a complete linux source tree for your kernel, not
  just an up-to-date kernel image, to compile the PCMCIA package.  The
  PCMCIA modules contain some references to kernel source files.  While
  you may want to build a new kernel to remove unnecessary drivers,
  installing PCMCIA does not require you to do so.

  Current ``stable'' kernel sources and patches are available from
  sunsite.unc.edu in /pub/Linux/kernel/v2.0, or from tsx-11.mit.edu in
  /pub/linux/sources/system/v2.0.  Current module utilities can be found
  in the same place, in modules-2.0.0.tgz.  Development kernels can be
  found in the corresponding v2.1 subdirectories.

  In the Linux source tree for 2.0 and 2.1 kernels, the
  Documentation/Changes file describes the versions of all sorts of
  other system components that are required for that kernel release.
  You may want to check through this and verify that your system is up
  to date, especially if you have updated your kernel.  If you are using
  a 2.1 kernel, be sure that you are using the right combination of
  shared libraries and module tools.  The latest versions of the module
  utilities, as well as versions for older kernels, can be found at
  <http://www.pi.se/blox/modules>.

  When configuring your kernel, if you plan on using a PCMCIA ethernet
  card, you should turn on networking support but turn off the normal
  Linux network card drivers, including the ``pocket and portable
  adapters''.  The PCMCIA network card drivers are all implemented as
  loadable modules.  Any drivers compiled into your kernel will only
  waste space.

  If you want to use SLIP, PPP, or PLIP, you do need to either configure
  your kernel with these enabled, or use the loadable module versions of
  these drivers.  There is an unfortunate deficiency in the kernel
  config process in 1.2.X kernels, in that it is not possible to set
  configuration options (like SLIP compression) for a loadable module,
  so it is probably better to just link SLIP into the kernel if you need
  it.

  If you want to use a PCMCIA token ring adapter, your kernel needs to
  be configured with ``Token Ring driver support'' (CONFIG_TR) enabled,
  though you should leave CONFIG_IBMTR off.

  If you want to use a PCMCIA IDE adapter, your kernel should be
  configured with CONFIG_BLK_DEV_IDE_PCMCIA enabled, for 1.3.72 through
  2.1.7 kernels.  Older kernels do not support removeable IDE devices;
  newer kernels do not require a special configuration setting.

  If you will be using a PCMCIA SCSI adapter, you should enable
  CONFIG_SCSI when configuring your kernel.  Also, enable any top level
  drivers (SCSI disk, tape, cdrom, generic) that you expect to use.  All
  low-level drivers for particular host adapters should be disabled, as
  they will just take up space.

  If you want to modularize a driver that is needed for a PCMCIA device,
  you must modify /etc/pcmcia/config to specify what modules need to be
  loaded for what card types.  For example, if the serial driver is
  modularized, then you could change the serial device definition to:

       device "serial_cs"
         class "serial" module "misc/serial", "serial_cs"

  This package includes an X-based card status utility called cardinfo.
  This utility is based on a freely distributed user interface toolkit
  called the Forms Library, which you will need to install before
  building cardinfo.  A binary distribution is on hyper.stanford.edu in
  /pub/pcmcia/extras: there are both a.out and ELF versions of the
  library.  You will also need to have all the normal X header files and
  libraries installed.

  2.2.  Installation

  Here is a synopsis of the installation process:

  ╖  Unpack pcmcia-cs-2.9.?.tar.gz in /usr/src.

  ╖  Run ``make config'' in the new pcmcia-cs-2.9.? directory.

  ╖  Run ``make all'', then ``make install''.

  ╖  Customize the PCMCIA startup script and the option files in
     /etc/pcmcia for your site.

  If you plan to install any contributed client drivers not included in
  the core PCMCIA distribution, unpack each of them in the top-level
  directory of the PCMCIA source tree.  Then follow the normal build
  instructions.  The extra drivers will be compiled and installed
  automatically.

  Running ``make config'' prompts for a few configuration options, and
  checks out your system to verify that it satisfies all prerequisites
  for installing PCMCIA support.  In most cases, you'll be able to just
  accept all the default configuration options.  Be sure to carefully
  check the output of this command in case there are problems.

  If you are compiling the PCMCIA package for installation on another
  machine, specify an alternate target directory when prompted by the
  configure script.  This should be an absolute path.  All the PCMCIA
  tools will be installed relative to this directory.  You will then be
  able to tar this directory tree and copy to your target machine, and
  unpack relative to its root directory to install everything in the
  proper places.

  If you are cross compiling on another machine, you may want to specify
  alternate names for the compiler and linker.  This may also be helpful
  on mixed a.out and ELF systems.  The script will also prompt for
  additional compiler flags for debugging.

  Some of the support utilities (cardctl and cardinfo) can be compiled
  either in ``safe'' or ``trusting'' forms.  The ``safe'' forms prevent
  non-root users from modifying card configurations.  The ``trusting''
  forms permit ordinary users to issue commands to suspend and resume
  cards, reset cards, and change the current configuration scheme.  The
  configuration script will ask if you want the utilities compiled as
  safe or trusting: the default is to be safe.

  There are a few kernel configuration options that affect the PCMCIA
  tools.  The configuration script can deduce these from the running
  kernel (the most common case).  Alternatively, if you are compiling
  for installation on another machine, it can read the configuration
  from a kernel source tree, or each option can be set interactively.

  Running ``make all'' followed by ``make install'' will build and then
  install the kernel modules and utility programs.  Kernel modules are
  installed under /lib/modules/<version>/pcmcia.  The cardmgr and
  cardctl programs are installed in /sbin.  If cardinfo is built, it is
  installed in /usr/bin/X11.

  Configuration files will be installed in the /etc/pcmcia directory.
  If you are installing over an older version, your old config scripts
  will be backed up before being replaced.  The saved scripts will be
  given extensions like *.~1~, *.~2~, and so on.

  If you don't know what kind of PCMCIA controller chip you have, you
  can use the probe utility in the cardmgr/ subdirectory to determine
  this.  There are two major types: the Databook TCIC-2 type and the
  Intel i82365SL-compatible type.

  A user-level daemon processes card insertion and removal events.  This
  is called cardmgr.  It is similar in function to Barry Jaspan's
  pcmciad in earlier PCMCIA releases.  Cardmgr reads a configuration
  file describing known PCMCIA cards from /etc/pcmcia/config.  This file
  also specifies what resources can be allocated for use by PCMCIA
  devices, and may need to be customized for your system.  See the
  pcmcia man page for more information about this file.

  2.3.  Post-installation for systems using BSD init scripts

  Some Linux distributions, including Slackware, use a BSD arrangement
  for system startup scripts.  If /etc/rc.d/rc.M exists, your system is
  in this group.  The script rc.pcmcia, installed in /etc/rc.d, controls
  starting up and shutting down the PCMCIA system.  ``make install''
  will use the probe command to determine your controller type and
  modify rc.pcmcia appropriately.  You should add a line to your system
  startup file /etc/rc.d/rc.M to invoke the PCMCIA startup script, like:

       /etc/rc.d/rc.pcmcia start

  It does not really matter where you insert this line, as long as the
  PCMCIA drivers are started after syslogd.

  2.4.  Post-installation for systems using System V init scripts

  Red Hat, Caldera, and Debian Linux have a System V-ish arrangement for
  system startup files.  If you have a directory called /etc/init.d or
  /etc/rc.d/init.d, then your system is in this group.  The rc.pcmcia
  script will be installed as /etc/rc.d/init.d/pcmcia, or
  /etc/init.d/pcmcia, as appropriate.  There is no need to edit any of
  the startup scripts to enable PCMCIA: it will happen automatically.

  If the /etc/sysconfig directory exists, then a separate configuration
  file, /etc/sysconfig/pcmcia, will be created for startup options.  If
  you need to change any module options (like the PCIC= or PCIC_OPTS=
  settings), edit this config file rather than the actual PCMCIA startup
  script.  This file will not be overwritten by subsequent installs.

  Some previous releases used the /etc/sysconfig/pcmcia-scripts
  directory in place of /etc/pcmcia on these platforms.  The current
  release instead uses /etc/pcmcia for all systems, and will move an
  existing /etc/sysconfig/pcmcia-scripts to /etc/pcmcia.

  2.5.  Site-specific configuration options

  Card Services should automatically avoid allocating IO ports and
  interrupts already in use by other standard devices.  It will also
  attempt to detect conflicts with unknown devices, but this is not
  completely reliable.  In some cases, you may need to explicitly
  exclude resources for a device in /etc/pcmcia/config.opts.

  Here are some resource settings for specific laptop types.

  ╖  On the AMS SoundPro, exclude irq 10.

  ╖  On some AMS TravelPro 5300 models, use memory 0xc8000-0xcffff.

  ╖  On the BMX 486DX2-66, exclude irq 5, irq 9.

  ╖  On the Chicony NB5, use memory 0xda000-0xdffff.

  ╖  On the Compaq Presario 1020, exclude port 0x2f8-0x2ff, irq 3, irq
     5.

  ╖  On the HP Omnibook 4000C, exclude port 0x300-0x30f.

  ╖  On the Micron Millenia Transport, exclude irq 5, irq 9.

  ╖  On the NEC Versa M, exclude irq 9, port 0x2e0-2ff.

  ╖  On the NEC Versa P/75, exclude irq 5, irq 9.

  ╖  On the NEC Versa S, exclude irq 9, irq 12.

  ╖  On the NEC Versa 6000 series, exclude port 0x300-0x33f, irq 9, irq
     10.

  ╖  On the ProStar 9200, Altima Virage, and Acquiline Hurricane
     DX4-100, exclude irq 5, port 0x330-0x35f.  Maybe use memory
     0xd8000-0xdffff.

  ╖  On the Siemens Nixdorf SIMATIC PG 720C, use memory 0xc0000-0xcffff,
     port 0x300-0x3bf.

  ╖  On the TI TravelMate 5000, use memory 0xd4000-0xdffff.

  ╖  On the Toshiba T4900 CT, exclude irq 5, port 0x2e0-0x2e8, port
     0x330-0x338.

  ╖  On the Twinhead 5100, HP 4000, Sharp PC-8700 and PC-8900, exclude
     irq 9 (sound), irq 12.

  ╖  On an MPC 800 Series, exclude irq 5, port 0x300-0x30f for the CD-
     ROM.

  Some PCMCIA controllers have optional features that may or may not be
  implemented in a particular system.  It is generally impossible for a
  socket driver to detect if these features are implemented.  Check the
  man page for your driver to see what optional features may be enabled.

  In a few cases, the probe command will be unable to determine your
  controller type automatically.  If you have a Halikan NBD 486 system,
  it has a TCIC-2 controller at an unusual location: you'll need to edit
  rc.pcmcia to load the tcic module, as well as setting the PCIC_OPTS
  parameter to ``tcic_base=0x02c0''.

  The low level socket drivers, tcic and i82365, have numerous bus
  timing parameters that may need to be adjusted for systems with
  particularly fast processors.  Symptoms of timing problems include
  card recognition problems, lock-ups under heavy loads, high error
  rates, or poor device performance.  Check the corresponding man pages
  for more details, but here is a brief summary:

  ╖  Cirrus controllers have numerous configurable timing parameters.
     The most important seems to be the cmd_time flag, which determines
     the length of PCMCIA bus cycles.  Fast 486 systems (i.e., DX4-100)
     seem to often benefit from increasing this from 6 (the default) to
     12 or 16.

  ╖  The Cirrus PD6729 PCI controller has the fast_pci flag, which
     should be set if the PCI bus speed is greater than 25 MHz.

  ╖  For Vadem VG-468 controllers and Databook TCIC-2 controllers, the
     async_clock flag changes the relative clocking of PCMCIA bus and
     host bus cycles.  Setting this flag adds extra wait states to some
     operations.  However, I have yet to hear of a laptop that needs
     this.

  ╖  The pcmcia_core module has the cis_speed parameter for changing the
     memory speed used for accessing a card's Card Information Structure
     (CIS).  On some systems with fast bus clocks, increasing this
     parameter (i.e., slowing down card accesses) may be beneficial for
     card recognition problems.

  ╖  This isn't a timing issue, but if you have more than one PCMCIA
     controller in your system or extra sockets in a docking station,
     the i82365 module should be loaded with the extra_sockets parameter
     set to 1.

  All these options should be configured by modifying the top of
  /etc/rc.d/rc.pcmcia.  For example:

       # Should be either i82365 or tcic
       PCIC=i82365
       # Put socket driver timing parameters here
       PCIC_OPTS="cmd_time=12"
       # Put pcmcia_core options here
       CORE_OPTS="cis_speed=500"

  Here are some timing settings for specific systems:

  ╖  On the ARM Pentium-90 or Midwest Micro Soundbook Plus, use
     ``freq_bypass=1 cmd_time=8''.

  ╖  On a Midwest Micro Soundbook Elite, use ``cmd_time=12''.

  ╖  On a Gateway Liberty, try ``cmd_time=16''.

  On some systems using Cirrus controllers, including the NEC Versa M,
  the BIOS puts the controller in a special suspended state at system
  startup time.  On these systems, the probe command will fail to find
  any known PCMCIA controller.  If this happens, edit
  /etc/rc.d/rc.pcmcia by hand as follows:

       # Should be either i82365 or tcic
       PCIC=i82365
       # Put socket driver timing parameters here
       PCIC_OPTS="wakeup=1"

  2.6.  Problems loading kernel modules

  The configure script will normally ensure that the PCMCIA modules are
  compatible with your kernel.  So, module loading problems generally
  indicate that the user has interfered with the normal installation
  process in some way.  Some module loading errors are sent directly to
  the Linux console.  Other errors are recorded in the system log file,
  normally /usr/adm/messages or /var/log/messages.  Depending on your
  syslogd configuration, some messages may be written to other files,
  but they will usually still be under /usr/adm or /var/log.  To track
  down a problem, be sure to check both locations, to pin down which
  module is actually causing trouble.

  Some of the PCMCIA modules require kernel services that may or may not
  be present, depending on kernel configuration.  For instance, the SCSI
  card drivers require that the kernel be configured with SCSI support,
  and the network drivers require a networking kernel.  If a kernel
  lacks a necessary feature, insmod may report undefined symbols and
  refuse to load a module.

  If insmod reports ``wrong version'' errors, it means that the module
  was compiled for a different kernel version than your system is
  actually running.  This might occur if modules compiled on one machine
  are copied to another machine with a different configuration, or if
  the kernel is reconfigured after PCMCIA is installed.

  Another source of module loading errors is when the modules and kernel
  were compiled with different settings of CONFIG_MODVERSIONS.  If a
  module with version checking is loaded against a kernel without
  version checking, insmod will complain about undefined symbols.

  Finally, relatively recent binutils releases are incompatible with
  older versions of the module utilities, and can cause module version
  incompatibilities to be reported.  The most common symptom is
  complaints about ``gcc_compiled'' being undefined.  If you get these
  errors, upgrade to the latest module utilities, available from
  <http://www.pi.se/blox/modules>.

  2.7.  Problems with the card status change interrupt

  In most cases, the socket driver (i82365 or tcic) will automatically
  probe and select an appropriate interrupt to signal card status
  changes.  The automatic interrupt probe doesn't work on some Intel-
  compatible controllers, including Cirrus chips and the chips used in
  some IBM ThinkPads.  If a device is inactive at probe time, its
  interrupt may also appear to be available.  In these cases, the socket
  driver may pick an interrupt that is used by another device.

  With the i82365 and tcic drivers, the irq_list option can be used to
  limit the interrupts that will be tested.  This list limits the set of
  interrupts that can be used by PCMCIA cards as well as for monitoring
  card status changes.  The cs_irq option can also be used to explicitly
  set the interrupt to be used for monitoring card status changes.

  If you can't find an interrupt number that works, there is also a
  polled status mode: both i82365 and tcic will accept a
  poll_interval=100 option, to poll for card status changes once per
  second.  This option should also be used if your system has a shortage
  of interrupts available for use by PCMCIA cards.  Especially for
  systems with more than one PCMCIA controller, there is little point in
  dedicating interrupts for monitoring card status changes.

  All these options should be set in the PCIC_OPTS= line in either
  /etc/rc.d/rc.pcmcia or /etc/sysconfig/pcmcia, depending on your site
  setup.

  2.8.  Card identification problems

  By default, the PCMCIA drivers allocate memory windows in the region
  0xc0000-0xfffff, after probing this region for conflicts with ROM or
  other devices.  This memory window is specified in
  /etc/pcmcia/config.opts.  The probe is done when the drivers first
  attempt to configure a new card.  The probe procedure is not
  foolproof, so it is possible for a conflict to go unrecognized.  If an
  address region that passes the probe is used by other devices in your
  system, cards may not be identified correctly.  With chipsets that
  support it, conflicts can also result from BIOS shadowing in this
  region.

  The classic symptom of a memory window configuration problem is that
  all cards will be misidentified as memory cards.  In unusual cases, a
  memory window conflict can interfere with a crucial system service,
  resulting in lock-ups or reboots.  If you suspect a memory window
  problem, first verify that ROM shadowing is disabled in your system's
  hardware setup.  Finding a good window may require some
  experimentation.  Some alternative windows to try are 0xd0000-0xdffff,
  0xc0000-0xc7fff, 0xc8000-0xcffff, or 0xd8000-0xdffff.

  If you have DOS PCMCIA drivers, you may be able to deduce what memory
  region those drivers use.  Note that DOS memory addresses are often
  specified in ``segment'' form, which leaves off the final hex digit
  (so an absolute address of 0xd0000 might be given as 0xd000).  Be sure
  to add the extra digit back when making changes to
  /etc/pcmcia/config.opts.

  If adjusting the memory window fails to solve a card identification
  problem, then it is likely to be due to a timing problem.

  2.9.  Why don't you distribute PCMCIA binaries?

  For me, distributing binaries is a significant hassle.  It is
  complicated because some features can only be selected at compile
  time, and because the PCMCIA modules are somewhat dependent on having
  the ``right'' kernel configuration.  So, I would probably need to
  distribute precompiled modules along with matching kernels.  Beyond
  this, the greatest need for precompiled modules is when installing
  Linux on a clean system.  This typically requires setting up PCMCIA so
  that it can be used in the installation process for a particular Linux
  distribution.  Each Linux distribution has its own procedures, and it
  is not feasible for me to provide boot and root disks for even just
  the common combinations of drivers and distributions.

  PCMCIA is now a part of many of the major Linux distributions,
  including Red Hat, Caldera, Slackware, Yggdrasil, Craftworks, and
  Nascent Technology.

  2.10.  Why is the PCMCIA package so darned big?

  Well, first of all, it isn't actually that large.  All the driver
  modules together take up about 200K of disk space.  The utility
  programs add up to about 70K, and the stuff in /etc/pcmcia is about
  30K.  When running, the core PCMCIA modules take up 48K of system
  memory.  The cardmgr daemon will generally be swapped out except when
  cards are inserted or removed.  The total package size is not much
  different from DOS Card Services implementations.

  Compared to DOS ``point enablers'', this may still seem like a lot of
  overhead, especially for people that don't plan on using many of the
  features of PCMCIA, such as power management or hot swapping.  Point
  enablers can be tiny because they generally support only one or a
  small set of cards, and also generally support a restricted set of
  PCMCIA controllers.  If someone were to write a genuinely ``generic''
  modem enabler, it would end up incorporating much of the functionality
  of Card Services, to handle cards from different vendors and the full
  range of PCMCIA controller variants.

  3.  Usage and features

  3.1.  Tools for monitoring PCMCIA devices

  The cardmgr daemon normally beeps when a card is inserted, and the
  tone of the beeps indicates the status of the newly inserted card.
  Two high beeps indicate the card was identified and configured
  successfully.  A high beep followed by a lower beep indicates that the
  card was identified, but could not be configured for some reason.  One
  low beep indicates that the card could not be identified.

  If the modules are all loaded correctly, the output of the lsmod
  command should look like the following, with no cards inserted:

       Module:        #pages:  Used by:
       ds                 2
       i82365             3
       pcmcia_core        7    [ds i82365]

  All the PCMCIA modules and the cardmgr daemon send status messages to
  the system log.  This will usually be /var/log/messages or
  /usr/adm/messages.  This file should be the first place to look when
  tracking down a problem.  When submitting a bug report, always include
  the contents of this file.  If you are having trouble finding your
  system messages, check /etc/syslogd.conf to see how different classes
  of messages are handled.

  Cardmgr also records some current device information for each socket
  in /var/run/stab.  Here is a sample /var/run/stab listing:

       Socket 0: Adaptec APA-1460 SlimSCSI
       0       scsi    aha152x_cs      0       sda     8       0
       0       scsi    aha152x_cs      1       scd0    11      0
       Socket 1: Serial or Modem Card
       1       serial  serial_cs       0       ttyS1   5       65

  For the lines describing devices, the first field is the socket, the
  second is the device class, the third is the driver name, the fourth
  is used to number multiple devices associated with the same driver,
  the fifth is the device name, and the final two fields are the major
  and minor device numbers for this device (if applicable).

  The cardctl command can be used to check the status of a socket, or to
  see how it is configured.  Here is an example of the output of the
  ``cardctl config'' command:

  Socket 0:
  Socket 1:
    Vcc = 5.0, Vpp1 = 0.0, Vpp2 = 0.0
    Card type is memory and I/O
    IRQ 3 is dynamic shared, level mode, enabled
    Speaker output is enabled
    Function 0:
      Config register base = 0x0800
        Option = 0x63, status = 0x08
      I/O window 1: 0x0280 to 0x02bf, auto sized
      I/O window 2: 0x02f8 to 0x02ff, 8 bit

  If you are running X, the cardinfo utility produces a graphical
  display showing the current status of all PCMCIA sockets, similar in
  content to ``cardctl config''.

  3.2.  Overview of the PCMCIA configuration scripts

  Each PCMCIA device has an associated ``class'' that describes how it
  should be configured and managed.  Classes are associated with device
  drivers in /etc/pcmcia/config.  There are currently five IO device
  classes (network, SCSI, cdrom, fixed disk, and serial) and two memory
  device classes (memory and FTL).  For each class, there are two
  scripts in /etc/pcmcia/config: a main configuration script (i.e.,
  /etc/pcmcia/scsi for SCSI devices), and an options script (i.e.,
  /etc/pcmcia/scsi.opts).  The main script for a device will be invoked
  to configure that device when a card is inserted, and to shut down the
  device when the card is removed.  For cards with several associated
  devices, the script will be invoked for each device.

  The config scripts start by extracting some information about a device
  from /var/run/stab.  Each script constructs a ``device address'', that
  uniquely describes the device it has been asked to configure, in the
  ADDRESS variable.  This is passed to the *.opts script, which should
  return information about how a device at this address should be
  configured.  For some devices, the device address is just the socket
  number.  For others, it includes extra information that may be useful
  in deciding how to configure the device.  For example, network devices
  pass their hardware ethernet address as part of the device address, so
  the network.opts script could use this to select from several
  different configurations.

  The first part of all device addresses is the current PCMCIA
  ``scheme''.  This parameter is used to support multiple sets of device
  configurations based on a single external user-specified variable.
  One use of schemes would be to have a ``home'' scheme, and a ``work''
  scheme, which would include different sets of network configuration
  parameters.  The current scheme is selected using the cardctl command.
  The default if no scheme is set is ``default''.

  As a general rule, when configuring Linux for a laptop, PCMCIA devices
  should only be configured from the PCMCIA device scripts.  Do not try
  to configure a PCMCIA device the same way you would configure a
  permanently attached device.

  3.3.  PCMCIA network adapters

  Linux ethernet-type network interfaces normally have names like eth0,
  eth1, and so on.  Token-ring adapters are handled similarly, however
  they are named tr0, tr1, and so on.  The ifconfig command is used to
  view or modify the state of a network interface.  A peculiarity of
  Linux is that network interfaces do not have corresponding device
  files under /dev, so don't be surprised when you can't find them.

  When a PCMCIA ethernet card is detected, it will be assigned the first
  free interface name, which will probably be eth0.  Cardmgr will run
  the /etc/pcmcia/network script to configure the interface.

  Do not configure your PCMCIA ethernet card in /etc/rc.d/rc.inet1,
  since the card may not be present when this script is executed.
  Comment out everything except the loopback stuff in rc.inet1.  If your
  system has an automatic network configuration procedure, you should
  generally indicate that you do not have a network card installed.
  Instead, edit the /etc/pcmcia/network.opts file to match your local
  network setup.  The network and network.opts scripts will be executed
  only when your ethernet card is actually present.

  The device address passed to network.opts consists of four comma-
  separated fields: the scheme, the socket number, the device instance,
  and the card's hardware ethernet address.  The device instance is used
  to number devices for cards that have several network interfaces, so
  it will usually be 0.  If you have several network cards used for
  different purposes, one option would be to configure the cards based
  on socket position, as in:

       case "$ADDRESS" in
       *,0,*,*)
           # definitions for network card in socket 0
           ;;
       *,1,*,*)
           # definitions for network card in socket 1
           ;;
       esac

  Alternatively, they could be configured using their hardware
  addresses, as in:

       case "$ADDRESS" in
       *,*,*,00:80:C8:76:00:B1)
           # definitions for a D-Link card
           ;;
       *,*,*,08:00:5A:44:80:01)
           # definitions for an IBM card
       esac

  To automatically mount and unmount NFS filesystems, first add all
  these filesystems to /etc/fstab, but include noauto in the mount
  options.  In network.opts, list the filesystem mount points in the
  MOUNTS variable.  It is especially important to use either cardctl or
  cardinfo to shut down a network card when NFS mounts are configured
  this way.  It is not possible to cleanly unmount NFS filesystems if a
  network card is simply ejected without warning.

  In addition to the usual network configuration parameters, the
  network.opts script can specify extra actions to be taken after an
  interface is configured, or before an interface is shut down.  If
  network.opts defines a shell function called start_fn, it will be
  invoked by the network script after the interface is configured, and
  the interface name will be passed to the function as its first (and
  only) argument.  Similarly, if it is defined, stop_fn will be invoked
  before shutting down an interface.

  3.3.1.  Transceiver selection

  The transceiver type can be selected in network.opts using the IF_PORT
  setting.  This can either be a numeric value as in previous PCMCIA
  releases, or a keyword identifying the transceiver type.  All the
  network drivers default to either autodetect the interface if
  possible, or 10baseT otherwise.  The ifport command can be used to
  check or set the current transceiver type.  For example:

       # ifport eth0 10base2
       #
       # ifport eth0
       eth0    2 (10base2)

  Current releases of the 3c589 driver attempt to autodetect the network
  connection, but this doesn't seem to be completely functional yet.
  For autodetection to work, the network cable should be connected to
  the card when the card is configured.  Alternatively, once the network
  is connected, you can force the driver to check the connection with:

       ifconfig eth0 down up

  3.3.2.  Comments about specific cards

  ╖  With IBM CCAE and Socket EA cards, you need to pick the transceiver
     type (10base2, 10baseT, AUI) when the network device is configured.
     Make sure that the transceiver type reported in the system log
     matches your connection.

  ╖  The drivers for SMC, Megahertz, Ositech, and 3Com cards should
     autodetect the attached network type (10base2 or 10baseT).  Setting
     the transceiver type when the driver is loaded serves to define the
     card's ``first guess''.

  ╖  The Farallon EtherWave is actually based on the 3Com 3c589, with a
     special transceiver.  Though the EtherWave uses 10baseT-style
     connections, its transceiver requires that the 3c589 be configured
     in 10base2 mode.

  ╖  If you have trouble with an IBM CCAE, NE4100, Thomas Conrad, or
     Kingston adapter, try increasing the memory access time with the
     mem_speed=# option to the pcnet_cs module.  An example of how to do
     this is given in the standard config.opts file.  Try speeds of up
     to 1000 (in nanoseconds).

  ╖  For the New Media Ethernet adapter, on some systems, it may be
     necessary to increase the IO port access time with the io_speed=#
     option when the pcmcia_core module is loaded.  Edit CORE_OPTS in
     the startup script  to set this option.

  ╖  The multicast support in the New Media Ethernet driver is
     incomplete.  The latest driver will function with multicast
     kernels, but will ignore multicast packets.  Promiscuous mode
     should work properly.

  ╖  The driver used by the IBM and 3Com token ring adapters seems to
     behave very badly if the cards are not connected to a ring when
     they get initialized.  Always connect these cards to the net before
     they are powered up.  This driver also requires free IO ports in
     the range of 0xa20-0xa27.  On some systems, the automatic IO port
     conflict checker will incorrectly determine that this port range is
     unavailable.  In that case, the port check can be disabled by
     loading the pcmcia_core module with probe_io=0.

  ╖  Newer Linksys and D-Link cards have a unique way of selecting the
     transceiver type that isn't handled by the Linux drivers.  One
     workaround is to boot DOS and use the vendor-supplied utility to
     select the transceiver, then warm boot Linux.  I am looking for
     beta testers for a Linux utility to perform this function.

  ╖  For WaveLAN wireless network adapters, Jean Tourrilhes
     ([e-mail]) has put together a wireless HOWTO at
     http://www-uk.hpl.hp.com/people/jt/Linux/Wavelan.html.

  3.3.3.  Diagnosing problems with network adapters

  ╖  Is your card recognized as an ethernet card?  Check the system log
     and make sure that cardmgr identifies the card correctly and starts
     up one of the network drivers.  If it doesn't, your card might
     still be usable if it is compatible with a supported card.  This
     will be most easily done if the card claims to be ``NE2000
     compatible''.

  ╖  Is the card configured properly?  If you are using a supported
     card, and it was recognized by cardmgr, but still doesn't work,
     there might be an interrupt or port conflict with another device.
     Find out what resources the card is using (from the system log),
     and try excluding these in /etc/pcmcia/config.opts to force the
     card to use something different.

  ╖  If your card seems to be configured properly, but sometimes locks
     up, particularly under high load, you may need to try changing your
     socket driver timing parameters.  See section ``2.3'' for more
     information.

  ╖  If you get messages like ``network unreachable'' when you try to
     access the network, then you have probably set up
     /etc/pcmcia/network.opts incorrectly.  On the other hand, mis-
     configured cards will usually fail silently.

  ╖  To diagnose problems in /etc/pcmcia/network.opts, start by trying
     to ping other systems on the same subnet using their IP addresses.
     Then try to ping your gateway, and then machines on other subnets.
     Ping machines by name only after trying these simpler tests.

  ╖  Make sure your problem is really a PCMCIA one.  It may help to see
     see if the card works under DOS with the vendor's drivers.  Double
     check your modifications to the /etc/pcmcia/network.opts script.
     Make sure your drop cable, ``T'' jack, terminator, etc are working.

  3.4.  PCMCIA serial and modem devices

  Linux serial devices are accessed via the /dev/cua* and /dev/ttyS*
  special device files.  The ttyS* devices are for incoming connections,
  such as directly connected terminals.  The cua* devices are for
  outgoing connections, such as modems.  Each physical serial port has
  both a ttyS and a cua device file: it is up to you to pick the
  appropriate device for your application.  The configuration of a
  serial device can be examined and modified with the setserial command.

  When a PCMCIA serial or modem card is detected, it will be assigned to
  the first available serial device slot.  This will usually be
  /dev/ttyS1 (cua1) or /dev/ttyS2 (cua2), depending on the number of
  built-in serial ports.  The ttyS* device is the one reported in
  /var/run/stab.  The default serial device option script,
  /etc/pcmcia/serial.opts, will link the corresponding cua* device file
  to /dev/modem as a convenience.

  Do not try to use /etc/rc.d/rc.serial to configure a PCMCIA modem.
  This script should only be used to configure non-removable devices.
  Modify /etc/pcmcia/serial.opts if you want to do anything special to
  set up your modem.  Also, do not try to change the IO port and
  interrupt settings of a PCMCIA serial device using setserial.  This
  would tell the serial driver to look for the device in a different
  place, but would not change how the card hardware is actually
  configured.  The serial configuration script allows you to specify
  other setserial options, as well as whether a line should be added to
  /etc/inittab for this port.

  The device address passed to serial.opts has three comma-separated
  fields: the first is the scheme, the second  is the socket number, and
  the third is the device instance.  The device instance may take
  several values for cards that support multiple serial ports, but for
  single-port cards, it will always be 0.  If you commonly use more than
  one PCMCIA modem, you may want to specify different settings based on
  socket position, as in:

       case "$ADDRESS" in
       *,0,*)
           # Options for modem in socket 0
           LINK=/dev/modem0
           ;;
       *,1,*)
           # Options for modem in socket 1
           LINK=/dev/modem1
           ;;
       esac

  If a PCMCIA modem is already configured when Linux boots, it may be
  incorrectly identified as an ordinary built-in serial port.  This is
  harmless, however, when the PCMCIA drivers take control of the modem,
  it will be assigned a different device slot.  It is best to either
  parse /var/run/stab or use /dev/modem, rather than expecting a PCMCIA
  modem to always have the same device assignment.

  If you configure your kernel to load the basic Linux serial port
  driver as a module, you must edit /etc/pcmcia/config to indicate that
  this module must be loaded.  Edit the serial device entry to read:

  device "serial_cs"
    class "serial" module "misc/serial", "serial_cs"

  3.4.1.  Diagnosing problems with serial devices

  ╖  Is your card recognized as a modem?  Check the system log and make
     sure that cardmgr identifies the card correctly and starts up the
     serial_cs driver.  If it doesn't, you may need to add a new entry
     to your /etc/pcmcia/config file so that it will be identified
     properly.  See section ``3.6'' for details.

  ╖  Is the modem configured successfully by serial_cs?  Again, check
     the system log and look for messages from the serial_cs driver.  If
     you see ``register_serial() failed'', you may have an I/O port
     conflict with another device.  Another tip-off of a conflict is if
     the device is reported to be an 8250; most modern PCMCIA modems
     should be identified as 16550A UART's.  If you think you're seeing
     a port conflict, edit /etc/pcmcia/config.opts and exclude the port
     range that was allocated for the modem.

  ╖  Is there an interrupt conflict?  If the system log looks good, but
     the modem just doesn't seem to work, try using setserial to change
     the irq to 0, and see if the modem works.  This causes the serial
     driver to use a slower polled mode instead of using interrupts.  If
     this seems to fix the problem, it is likely that some other device
     in your system is using the interrupt selected by serial_cs.  You
     should add a line to /etc/pcmcia/config.opts to exclude this
     interrupt.

  ╖  If the modem seems to work only very, very slowly, this is an
     almost certain indicator of an interrupt conflict.

  ╖  Make sure your problem is really a PCMCIA one.  It may help to see
     if the card works under DOS with the vendor's drivers.  Also, don't
     test the card with something complex like SLIP or PPP until you are
     sure you can make simple connections.  If simple things work but
     SLIP does not, your problem is most likely with SLIP, not with
     PCMCIA.

  ╖  If you get kernel messages indicating that the serial_cs module
     cannot be loaded, it means that your kernel does not have serial
     device support.  If you have compiled the serial driver as a
     module, you must modify /etc/pcmcia/config to indicate that the
     serial module should be loaded before serial_cs.

  3.5.  PCMCIA SCSI adapters

  All the currently supported PCMCIA SCSI cards are work-alikes of one
  of the following ISA bus cards: the Qlogic, the Adaptec AHA-152X, or
  the Future Domain TMC-16x0.  The PCMCIA drivers are built by linking
  some PCMCIA-specific code (in qlogic_cs.c, toaster_cs.c, or
  fdomain_cs.c) with the normal Linux SCSI driver.

  When a new SCSI host adapter is detected, the SCSI drivers will probe
  for devices.  Check the system log to make sure your devices are
  detected properly.  New SCSI devices will be assigned to the first
  available SCSI device files.  The first SCSI disk will be /dev/sda,
  the first SCSI tape will be /dev/st0, and the first CD-ROM will be
  /dev/scd0.
  With 1.3.X and later kernels, the PCMCIA core drivers are able to find
  out from the kernel which SCSI devices are connected to a card.  They
  will be listed in /var/run/stab, and the SCSI configuration script,
  /etc/pcmcia/scsi, will be called once for each attached device, to
  either configure or shut down that device.  The default script does
  not take any actions to configure SCSI devices, but will properly
  unmount filesystems on SCSI devices when a card is removed.

  With 1.2.X kernels, the PCMCIA drivers cannot automatically deduce
  which devices are associated with a particular SCSI adapter.  Instead,
  if you have one normal SCSI device configuration, you may list these
  devices in /etc/pcmcia/scsi.opts.  For example, if you normally have a
  SCSI disk and a CD-ROM, you would use:

       # For 1.2 kernels: list of attached devices
       SCSI_DEVICES="sda scd0"

  The device addresses passed to scsi.opts are complicated, because of
  the variety of things that can be attached to a SCSI adapter.
  Addresses consist of either six or seven comma-separated fields: the
  current scheme, the device type, the socket number, the SCSI channel,
  ID, and logical unit number, and optionally, the partition number.
  The device type will be ``sd'' for disks, ``st'' for tapes, ``sr'' for
  CD-ROM devices, and ``sg'' for generic SCSI devices.  For most setups,
  the SCSI channel and logical unit number will be 0.  For disk devices
  with several partitions, scsi.opts will first be called for the whole
  device, with a five-field address.  The script should set the PARTS
  variable to a list of partitions.  Then, scsi.opts will be called for
  each partition, with the longer seven-field addresses.  For example,
  here is a script for configuring a disk device at SCSI ID 3, with two
  partitions, and a CD-ROM at SCSI ID 6:

  case "$ADDRESS" in
  *,sd,*,0,3,0)
      # This device has two partitions...
      PARTS="1 2"
      ;;
  *,sd,*,0,3,0,1)
      # Options for partition 1:
      #  update /etc/fstab, and mount an ext2 fs on /usr1
      DO_FSTAB="y" ; DO_FSCK="y" ; DO_MOUNT="y"
      FSTYPE="ext2"
      OPTS=""
      MOUNTPT="/usr1"
      ;;
  *,sd,*,0,3,0,2)
      # Options for partition 2:
      #  update /etc/fstab, and mount an MS-DOS fs on /usr2
      DO_FSTAB="y" ; DO_FSCK="y" ; DO_MOUNT="y"
      FSTYPE="msdos"
      OPTS=""
      MOUNTPT="/usr2"
      ;;
  *,sr,*,0,6,0)
      # Options for CD-ROM at SCSI ID 6
      PARTS=""
      DO_FSTAB="y" ; DO_FSCK="n" ; DO_MOUNT="y"
      FSTYPE="iso9660"
      OPTS="ro"
      MOUNTPT="/cdrom"
      ;;
  esac

  If your kernel does not have a top-level driver (disk, tape, etc) for
  a particular SCSI device, then the device will not be configured by
  the PCMCIA drivers.  As a side effect, the device's name in
  /var/run/stab will be something like ``sd#nnnn'' where ``nnnn'' is a
  four-digit hex number.  This happens when cardmgr is unable to
  translate a SCSI device ID into a corresponding Linux device name.

  It is possible to modularize the top-level SCSI drivers so that they
  are only loaded when a PCMCIA SCSI adapter is detected.  To do so, you
  need to edit /etc/pcmcia/config to tell cardmgr which extra modules
  need to be loaded when your adapter is configured.  For example:

       device "aha152x_cs"
         class "scsi" module "scsi/scsi_mod", "scsi/sd_mod", "aha152x_cs"

  would say to load the core SCSI module and the top-level disk driver
  module before loading the regular PCMCIA driver module.  The PCMCIA
  Configure script will not automatically detect modularized SCSI
  modules, so you will need use the manual configure option to enable
  SCSI support.

  Always turn on SCSI devices before powering up your laptop, or before
  inserting the adapter card, so that the SCSI bus is properly
  terminated when the adapter is configured.  Also be very careful about
  ejecting a SCSI adapter.  Be sure that all associated SCSI devices are
  unmounted and closed before ejecting the card.  The best way to ensure
  this is to use either cardctl or cardinfo to request card removal
  before physically ejecting the card.  For now, all SCSI devices should
  be powered up before plugging in a SCSI adapter, and should stay
  connected until after you unplug the adapter and/or power down your
  laptop.

  There is a potential complication when using these cards that does not
  arise with ordinary ISA bus adapters.  The SCSI bus carries a
  ``termination power'' signal that is necessary for proper operation of
  ordinary passive SCSI terminators.  PCMCIA SCSI adapters do not supply
  termination power, so if it is required, an external device must
  supply it.  Some external SCSI devices may be configured to supply
  termination power.  Others, such as the Zip Drive and the Syquest EZ-
  Drive, use active terminators that do not depend on it.  In some
  cases, it may be necessary to use a special terminator block such as
  the APS SCSI Sentry 2, which has an external power supply.  When
  configuring your SCSI device chain, be aware of whether or not any of
  your devices require or can provide termination power.

  The Adaptec APA-460 SlimSCSI adapter is not supported.  This card was
  originally sold under the Trantor name, and when Adaptec merged with
  Trantor, they continued to sell the Trantor card with an Adaptec
  label.  The APA-460 is not compatible with any existing Linux driver.
  I'm not sure how hard it would be to write a driver; I don't think
  anyone has been able to obtain the technical information from Adaptec.

  The (unsupported) Trantor SlimSCSI can be identified by the following:

       Trantor / Adaptec APA-460 SlimSCSI
       FCC ID: IE8T460
       Shipped with SCSIworks! driver software

  The (supported) Adaptec SlimSCSI can be identified by the following:

       Adaptec APA-1460 SlimSCSI
       FCC ID: FGT1460
       P/N: 900100
       Shipped with EZ-SCSI driver software

  3.5.1.  Diagnosing problems with SCSI adapters

  ╖  With the aha152x_cs driver (used by Adaptec, New Media, and a few
     others), it seems that SCSI disconnect/reconnect support is a
     frequent source of trouble with tape drives.  To disable this
     ``feature,'' add the following to /etc/pcmcia/config.opts:

       module "aha152x_cs" opts "reconnect=0"

  ╖  If you have compiled SCSI support as modules (CONFIG_SCSI is
     ``m''), when configuring PCMCIA, you must explicitly specify that
     you want the SCSI drivers to be built.  You must also modify
     /etc/pcmcia/config to load the SCSI modules before the appropriate
     *_cs driver is loaded.

  3.6.  PCMCIA memory cards

  The memory_cs driver handles all types of memory cards, as well as
  providing direct access to the PCMCIA memory address space for cards
  that have other functions.  When loaded, it creates a combination of
  character and block devices.  See the man page for the module for a
  complete description of the device naming scheme.  Block devices are
  used for disk-like access (creating and mounting filesystems, etc).
  The character devices are for "raw" unbuffered reads and writes at
  arbitrary locations.

  The device address passed to memory.opts consists of two fields: the
  scheme, and the socket number.  The options are applied to the first
  common memory partition on the corresponding memory card.  Here is an
  example of a script that will automatically mount memory cards based
  on which socket they are inserted into:

       case "$ADDRESS" in
       *,0,0)
           # Mount filesystem, but don't update /etc/fstab
           DO_FSTAB="n" ; DO_FSCK="y" ; DO_MOUNT="y"
           FSTYPE="ext2" ; OPTS=""
           MOUNTPT="/mem0"
           ;;
       *,1,0)
           # Mount filesystem, but don't update /etc/fstab
           DO_FSTAB="n" ; DO_FSCK="y" ; DO_MOUNT="y"
           FSTYPE="ext2" ; OPTS=""
           MOUNTPT="/mem1"
           ;;
       esac

  Some older memory cards, and most simple static RAM cards, lack a
  ``Card Information Structure'' (CIS), which is the scheme PCMCIA cards
  use to identify themselves.  Normally, cardmgr will assume that any
  card that lacks a CIS is a simple memory card, and load the memory_cs
  driver.  Thus, a common side effect of a general card identification
  problem is that other types of cards may be misdetected as memory
  cards.

  The memory_cs driver uses a heuristic to guess the capacity of these
  cards.  The heuristic does not work for write protected cards, and may
  make mistakes in some other cases as well.  If a card is misdetected,
  its size should then be explicitly specified when using commands such
  as dd or mkfs.

  3.6.1.  Using flash memory cards

  The device address passed to ftl.opts consists of three or four
  fields: the scheme, the socket number, the region number, and
  optionally, the partition number.  Most flash cards have just one
  flash memory region, so the region number will generally always be
  zero.

  To use a flash memory card as an ordinary disk-like block device,
  first create a ``flash translation layer'' partition on the device
  with the ftl_format command:

       ftl_format -i /dev/mem0c0c

  Note that this command accesses the card through the ``raw'' memory
  card interface.  Once formatted, the card can be accessed as an
  ordinary block device via the ftl_cs driver.  For example:

       mke2fs /dev/ftl0c0
       mount -t ext2 /dev/ftl0c0 /mnt

  Device naming for FTL devices is tricky.  Minor device numbers have
  three parts: the card number, the region number on that card, and
  optionally, the partition within that region.  A region can either be
  treated as a single block device with no partition table (like a
  floppy), or it can be partitioned like a hard disk device.  The
  ``ftl0c0'' device is card 0, common memory region 0, the entire
  region.  The ``ftl0c0p1'' through ``ftl0c0p4'' devices are primary
  partitions 1 through 4 if the region has been partitioned.

  There are two major formats for flash memory cards: the ``flash
  translation layer'' style, and the Microsoft Flash File System.  The
  FTL format is generally more flexible because it allows any ordinary
  high-level filesystem (ext2, ms-dos, etc) to be used on a flash card
  as if it were an ordinary disk device.  The FFS is a completely
  different filesystem type.  Linux cannot currently handle cards
  formated with FFS.

  3.7.  PCMCIA ATA/IDE card drives

  ATA/IDE drive support requires a 1.3.72 or higher kernel.  The PCMCIA-
  specific part of the driver is fixed_cs.  Be sure to use cardctl or
  cardinfo to shut down an ATA/IDE card before ejecting it, as the
  driver has not been made ``hot-swap-proof''.

  The device addresses passed to fixed.opts consist of either three or
  four fields: the current scheme, the socket number, the drive's serial
  number, and an optional partition number.  As with SCSI devices,
  fixed.opts is first called for the entire device.  If fixed.opts
  returns a list of partitions in the PARTS variable, the script will
  then be called for each partition.

  Here is an example fixed.opts file to mount the first partition of any
  ATA/IDE card on /mnt.

  case "$ADDRESS" in
  *,*,*)
      PARTS="1"
      ;;
  *,*,*,1)
      DO_FSTAB="y" ; DO_FSCK="y" ; DO_MOUNT="y"
      FSTYPE="msdos"
      OPTS=""
      MOUNTPT="/mnt"
      ;;
  esac

  Note that the default fixed.opts file has these lines but they are
  commented out.  If you wish, you can have separate configurations for
  specific cards based on their serial numbers.  To find out a drive's
  serial number, use the ide_info utility.  Then, part of fixed.opts
  might look like:

       case "$ADDRESS" in
       *,*,Z4J60542)
           # This is my DOS stuff
           PARTS="1"
           ;;
       *,*,Z4J60542,1)
           DO_FSTAB="y" ; DO_FSCK="y" ; DO_MOUNT="y"
           FSTYPE="msdos"
           OPTS=""
           MOUNTPT="/mnt"
           ;;
       esac

  3.7.1.  Diagnosing problems with ATA/IDE adapters

  ╖  Some IDE drives violate the PCMCIA specification by requiring a
     longer time to spin up than the maximum allowed card setup time.
     To use these cards, load the pcmcia_core module with:

       CORE_OPTS="unreset_delay=400"

  ╖  To use an ATA/IDE CD-ROM device, your kernel must be compiled with
     CONFIG_BLK_DEV_IDECD enabled.  This will normally be the case for
     standard kernels, however it is something to be aware of if you
     compile a custom kernel.

  3.8.  Multifunction cards

  Starting with the 1.3.73 Linux kernel, a single interrupt can be
  shared by several drivers, such as the serial driver and an ethernet
  driver.  When using a multifunction card under a newer kernel, all
  card functions can be used without loading and unloading drivers.

  Simultaneous use of two card functions is ``tricky'' and various
  hardware vendors have implemented interrupt sharing in their own
  incompatible (and sometimes proprietary) ways.  The drivers for some
  cards (Ositech Jack of Diamonds, 3Com 3c562, Linksys) properly support
  simultaneous access, but others (Megahertz in particular) do not.

  Earlier kernels do not support interrupt sharing between different
  device drivers, so it is not possible for the PCMCIA drivers to
  configure this card for simultaneous ethernet and modem access.  The
  ethernet and serial drivers are both loaded automatically.  However,
  the ethernet driver ``owns'' the card interrupt by default.  To use
  the modem, you can unload the ethernet driver and reconfigure the
  serial port by doing something like:

       ifconfig eth0 down
       rmmod 3c589_cs
       setserial /dev/modem autoconfig auto_irq
       setserial /dev/modem

  The second setserial should verify that the port has been configured
  to use the interrupt previously used by the ethernet driver.

  3.9.  When is it safe to insert or eject a PCMCIA card?

  In theory, you can insert and remove PCMCIA cards at any time.
  However, it is a good idea not to eject a card that is currently being
  used by an application program.  Kernels older than 1.1.77 would often
  lock up when serial/modem cards were ejected, but this should be fixed
  now.

  3.10.  Card Services and Advanced Power Management

  Card Services can be compiled with support for APM (Advanced Power
  Management) if you've installed this package on your system.  APM is
  incorporated into 1.3.46 and later kernels.  It is currently being
  maintained by Rick Faith ([e-mail]), and APM tools can be
  obtained from ftp.cs.unc.edu in /pub/users/faith/linux.  The PCMCIA
  modules will automatically be configured for APM if a compatible
  version is detected on your system.

  Without resorting to APM, you can do ``cardctl suspend'' before
  suspending your laptop, and ``cardctl resume'' after resuming, to
  properly shut down and restart your PCMCIA cards.  This will not work
  with a PCMCIA modem that is in use, because the serial driver isn't
  able to save and restore the modem operating parameters.

  APM seems to be unstable on some systems.  If you experience trouble
  with APM and PCMCIA on your system, try to narrow down the problem to
  one package or the other before reporting a bug.

  Some drivers, notably the PCMCIA SCSI drivers, cannot recover from a
  suspend/resume cycle.  When using a PCMCIA SCSI card, use ``cardctl
  eject'' prior to suspending the system.

  3.11.  How do I turn off a PCMCIA card without ejecting it?

  Use either the cardctl or cardinfo command.  ``cardctl suspend #''
  will suspend one socket, and turn off its power.  The corresponding
  resume command will wake up the card in its previous state.

  3.12.  How do I unload the PCMCIA drivers?

  To unload the entire PCMCIA package, invoke rc.pcmcia with:

       /etc/rc.d/rc.pcmcia stop

  This script will take several seconds to run, to give all client
  drivers time to shut down gracefully.  If a PCMCIA device is currently
  in use, the shutdown will be incomplete, and some kernel modules may
  not be unloaded.  To avoid this, use ``cardctl eject'' to shut down
  all sockets before invoking rc.pcmcia.  The exit status of the cardctl
  command will indicate if any sockets could not be shut down.

  4.  Advanced topics

  4.1.  Resource allocation for PCMCIA devices

  In theory, it should not really matter which interrupt is allocated to
  which device, as long as two devices are not configured to use the
  same interrupt.  In /etc/pcmcia/config.opts you'll find a place for
  excluding interrupts that are used by non-PCMCIA devices.

  Similarly, there is no way to directly specify the I/O addresses for a
  PCMCIA card to use.  The /etc/pcmcia/config.opts file allows you to
  specify ranges of ports available for use by all PCMCIA devices, or to
  exclude ranges that conflict with other devices.

  After modifying /etc/pcmcia/config.opts, you can restart cardmgr with
  ``kill -HUP''.

  The interrupt used to monitor card status changes is chosen by the
  low-level socket driver module (i82365 or tcic) before cardmgr parses
  /etc/pcmcia/config, so it is not affected by changes to this file.  To
  set this interrupt, use the cs_irq= option when the socket driver is
  loaded, by setting the PCIC_OPTS variable in /etc/rc.d/rc.pcmcia.

  All the client card drivers have a parameter called irq_list for
  specifying which interrupts they may try to allocate.  These driver
  options should be set in your /etc/pcmcia/config file.  For example:

       device "serial_cs"
         module "serial_cs" opts "irq_list=8,12"
         ...

  would specify that the serial driver should only use irq 8 or irq 12.
  Regardless of irq_list settings, Card Services will never allocate an
  interrupt that is already in use by another device, or an interrupt
  that is excluded in the config file.

  4.2.  How can I have separate device setups for home and work?

  This is fairly easy using PCMCIA ``scheme'' support.  Use two
  configuration schemes, called ``home'' and ``work''.  Here is an
  example of a network.opts script with scheme-specific settings:

       case "$ADDRESS" in
       work,*,*,*)
           # definitions for network card in work scheme
           ...
           ;;
       home,*,*,*|default,*,*,*)
           # definitions for network card in home scheme
           ...
           ;;
       esac

  The first part of a PCMCIA device address is always the configuration
  scheme.  In this example, the second ``case'' clause will select for
  both the ``home'' and ``default'' schemes.  So, if the scheme is unset
  for any reason, it will default to the ``home'' setup.

  Now, to choose between the two sets of settings, run either:

       cardctl scheme home

  or

       cardctl scheme work

  The cardctl command does the equivalent of shutting down all your
  cards and restarting them.  The command can be safely executed whether
  or not the PCMCIA system is loaded, but the command may fail if you
  are using other PCMCIA devices at the time (even if their
  configurations are not explicitly dependant on the scheme setting).

  To find out the current PCMCIA scheme setting, run:

       cardctl scheme

  4.3.  Booting from a PCMCIA device

  Having the root filesystem on a PCMCIA device is tricky because the
  Linux PCMCIA system is not designed to be linked into the kernel.  Its
  core components, the loadable kernel modules and the user mode cardmgr
  daemon, depend on an already running system.  The kernel's ``initrd''
  facility works around this requirement by allowing Linux to boot using
  a temporary ram disk as a minimal root image, load drivers, and then
  re-mount a different root filesystem.  The temporary root can
  configure PCMCIA devices and then re-mount a PCMCIA device as root.

  Some Linux distributions will allow installation to a device connected
  to a PCMCIA SCSI adapter, as an unintended side-effect of their
  support for installs from PCMCIA SCSI CD-ROM devices.  However, at
  present, no Linux installation tools support configuring an
  appropriate ``initrd'' to boot Linux with a PCMCIA root filesystem.
  Setting up a system with a PCMCIA root thus requires that you use
  another Linux system to create the ``initrd'' image.  If another Linux
  system is not available, another option would be to temporarily
  install a minimal Linux setup on a non-PCMCIA drive, create an initrd
  image, and then reinstall to the PCMCIA target.

  The Linux Bootdisk-HOWTO has some general information about setting up
  boot disks but nothing specific to initrd.  The main initrd document
  is included with recent kernel source code distributions, in
  linux/Documentation/initrd.txt.  Before beginning, you should read
  this document.  A familiarity with lilo is also helpful.  Using initrd
  also requires that you have a kernel compiled with CONFIG_BLK_DEV_RAM
  and CONFIG_BLK_DEV_INITRD enabled.

  4.3.1.  The pcinitrd helper script

  The pcinitrd script creates a basic initrd image for booting with a
  PCMCIA root partition.  The image includes a minimal directory
  heirarchy, a handful of device files, a few binaries, shared
  libraries, and a set of PCMCIA driver modules.  When invoking
  pcinitrd, you specify the driver modules that you want to be included
  in the image.  The core PCMCIA components, pcmcia_core and ds, are
  automatically included.

  As an example, say that your laptop uses an i82365-compatible PCMCIA
  host controller, and you want to boot Linux with the root filesystem
  on a hard drive attached to an Adaptec SlimSCSI adapter.  You could
  create an appropriate initrd image with:

       pcinitrd -v initrd pcmcia/i82365.o pcmcia/aha152x_cs.o

  To customize the initrd startup sequence, you could mount the image
  using the ``loopback'' device with a command like:

       mount -o loop -t ext2 initrd /mnt

  and then edit the linuxrc script.  The PCMCIA configuration files will
  be installed under /etc in the image, and can also be customized.  See
  the man page for pcinitrd for more information.

  4.3.2.  Creating an initrd boot floppy

  After creating an image with pcinitrd, you can create a boot floppy by
  copying the kernel, the compressed initrd image, and a few support
  files for lilo to a clean floppy.  In the following example, we assume
  that the desired PCMCIA root device is /dev/sda1:

       mke2fs /dev/fd0
       mount /dev/fd0 /mnt
       mkdir /mnt/etc /mnt/boot /mnt/dev
       cp -a /dev/fd0 /dev/sda1 /mnt/dev
       cp [kernel-image] /mnt/vmlinuz
       gzip < [initrd-image] > /mnt/initrd

  Create /mnt/etc/lilo.conf with the contents:

       boot=/dev/fd0
       compact
       image=/vmlinuz
           label=linux
           initrd=/initrd
           read-only
           root=/dev/sda1

  Finally, invoke lilo with:

       lilo -r /mnt

  When lilo is invoked with -r, it performs all actions relative to the
  specified alternate root directory.  The reason for creating the
  device files under /mnt/dev was that lilo will not be able to use the
  files in /dev when it is running in this alternate-root mode.

  4.3.3.  Installing an initrd image on a non-Linux drive

  One common use of the initrd facility would be on systems where the
  internal hard drive is dedicated to another operating system.  The
  Linux kernel and initrd image can be placed in a non-Linux partition,
  and lilo or LOADLIN can be set up to boot Linux from these images.

  Assuming that you have a kernel has been configured for the
  appropriate root device, and an initrd image created on another
  system, the easiest way to get started is to boot Linux using LOADLIN,
  as:

       LOADLIN <kernel> initrd=<initrd-image>

  Once you can boot Linux on your target machine, you could then install
  lilo to allow booting Linux directly.  For example, say that /dev/hda1
  is the non-Linux target partition and /mnt can be used as a mount
  point.  First, create a subdirectory on the target for the Linux
  files:

       mount /dev/hda1 /mnt
       mkdir /mnt/linux
       cp [kernel-image] /mnt/linux/vmlinuz
       cp [initrd-image] /mnt/linux/initrd

  In this example, say that /dev/sda1 is the desired Linux root
  partition, a SCSI hard drive mounted via a PCMCIA SCSI adapter.  To
  install lilo, create a lilo.conf file with the contents:

       boot=/dev/hda
       map=/mnt/linux/map
       compact
       image=/mnt/linux/vmlinuz
               label=linux
               root=/dev/sda1
               initrd=/mnt/linux/initrd
               read-only
       other=/dev/hda1
               table=/dev/hda
               label=windows

  The boot= line says to install the boot loader in the master boot
  record of the specified device.  The root= line identifies the desired
  root filesystem to be used after loading the initrd image, and may be
  unnecessary if the kernel image is already configured this way.  The
  other= section is used to describe the other operating system
  installed on /dev/hda1.

  To install lilo in this case, use:

       lilo -C lilo.conf

  Note that in this case, the lilo.conf file uses absolute paths that
  include /mnt.  I did this in the example because the target filesystem
  may not support the creation of Linux device files for the boot= and
  root= options.

  5.  Dealing with unsupported cards

  5.1.  Configuring unrecognized cards

  Assuming that your card is supported by an existing driver, all that
  needs to be done is to add an entry to /etc/pcmcia/config to tell
  cardmgr how to identify the card, and which driver(s) need to be
  linked up to this card.  Check the man page for pcmcia for more
  information about the config file format.  If you insert an unknown
  card, cardmgr will normally record some identification information in
  the system log that can be used to construct the config entry.

  Here is an example of how cardmgr will report an unsupported card in
  /usr/adm/messages.

       cardmgr[460]: unsupported card in socket 1
       cardmgr[460]: version info: "MEGAHERTZ", "XJ2288", "V.34 PCMCIA MODEM"

  The corresponding entry in /etc/pcmcia/config would be:

       card "Megahertz XJ2288 V.34 Fax Modem"
         version "MEGAHERTZ", "XJ2288", "V.34 PCMCIA MODEM"
         bind "serial_cs"

  You can use ``*'' to match strings that don't need to match exactly,
  like version numbers.  When making new config entries, be careful to
  copy the strings exactly, preserving case and blank spaces.  Also be
  sure that the config entry has the same number of strings as are
  reported in the log file.

  After editing /etc/pcmcia/config, you can signal cardmgr to reload the
  file with:

       kill -HUP `cat /var/run/cardmgr.pid`

  If you do set up an entry for a new card, please send me a copy so
  that I can include it in the standard config file.

  5.2.  Adding support for an NE2000-compatible ethernet card

  First, see if the card is already recognized by cardmgr.  Some cards
  not listed in SUPPORTED.CARDS are actually OEM versions of cards that
  are supported.  If you find a card like this, let me know so I can add
  it to the list.

  If your card is not recognized, follow the instructions in section
  ``3.6'' to create a config entry for your card, and bind the card to
  the pcnet_cs driver.  Restart cardmgr to use the updated config file.

  If the pcnet_cs driver says that it is unable to determine your card's
  hardware ethernet address, then edit your new config entry to bind the
  card to the memory card driver, memory_cs.  Restart cardmgr to use the
  new updated config file.  You will need to know your card's hardware
  ethernet address.  This address is a series of six two-digit hex
  numbers, often printed on the card itself.  If it is not printed on
  the card, you may be able to use a DOS driver to display the address.
  In any case, once you know it, run:

       dd if=/dev/mem0a count=20 | od -Ax -t x1

  and search the output for your address.  Only the even bytes are
  defined, so ignore the odd bytes in the dump.  Record the hex offset
  of the first byte of the address.  Now, edit modules/pcnet_cs.c and
  find the hw_info structure.  You'll need to create a new entry for
  your card.  The first field is the memory offset.  The next three
  fields are the first three bytes of the hardware address.  The final
  field contains some flags for specific card features; to start, try
  setting it to 0.

  After editing pcnet_cs.c, compile and install the new module.  Edit
  /etc/pcmcia/config again, and change the card binding from memory_cs
  to pcnet_cs.  Follow the instructions for reloading the config file,
  and you should be all set.  Please send me copies of your new hw_info
  and config entries.

  If you can't find your card's hardware address in the hex dump, as a
  method of last resort, it is possible to ``hard-wire'' the address
  when the pcnet_cs module is initialized.  Edit /etc/pcmcia/config and
  add a hw_addr= option, like so:

       module "pcnet_cs" opts "hw_addr=0x00,0x80,0xc8,0x01,0x02,0x03"

  Substitute your own card's hardware address in the appropriate spot,
  of course.

  5.3.  PCMCIA floppy interface cards

  The PCMCIA floppy interface used in the Compaq Aero and a few other
  laptops is not yet supported by this package.  The snag in supporting
  the Aero floppy is that the Aero seems to use a customized PCMCIA
  controller to support DMA to the floppy.  Without knowing exactly how
  this is done, there isn't any way to implement support under Linux.

  If the floppy adapter card is present when an Aero is booted, the Aero
  BIOS will configure the card, and Linux will identify it as a normal
  floppy drive.  When the Linux PCMCIA drivers are loaded, they will
  notice that the card is already configured and attached to a Linux
  driver, and this socket will be left alone.  So, the drive can be used
  if it is present at boot time, but the card is not hot swappable.

  5.4.  What's up with support for Xircom cards?

  A driver for Xircom ethernet and ethernet/modem cards is included in
  the current PCMCIA package, thanks to the work of Werner Koch.  I've
  set up a HyperNews forum specifically for discussion of Xircom driver
  development, at
  http://hyper.stanford.edu/HyperNews/get/pcmcia/xircom.html.

  For a long time, Xircom cards were not supported because Xircom had a
  company policy of not disclosing technical information about their
  cards.  However, they have relaxed their rules, and now, they do
  distribute driver information.

  6.  Debugging tips and programming information

  6.1.  How can I submit a helpful bug report?

  The best way to submit bug reports is to use the HyperNews message
  lists on the Linux PCMCIA information site.  That way, other people
  can see current problems (and fixes or workarounds, if available).
  Here are some things that should be included in all bug reports:

  ╖  Your system type, and the output of the probe command.

  ╖  What PCMCIA cards you are using.

  ╖  Your Linux kernel version, and PCMCIA driver version.

  ╖  Any changes you've made to the startup files in /etc/pcmcia, or to
     the PCMCIA startup script.

  ╖  All PCMCIA-related messages in your system log file.

  Before submitting a bug report, please check to make sure that you are
  using an up-to-date copy of the driver package.  While it is somewhat
  gratifying to read bug reports for things I've already fixed, it isn't
  a particularly constructive use of my time.

  If your problem involves a kernel fault, the register dump from the
  fault is only useful if you can track down the fault address, EIP.  If
  it is in the main kernel, look up the address in System.map to
  identify the function at fault.  If the fault is in a loadable module,
  it is a bit harder to trace.  With the current module tools, ``ksyms
  -m'' will report the base address of each loadable module.  Pick the
  module that contains the EIP address, and subtract its base address
  from EIP to get an offset inside that module.  Then, run gdb on that
  module, and look up the offset with the list command.  This will only
  work if you've compiled that module with -g to include debugging
  information.

  If you do not have web access, bug reports can be sent to me at
  [e-mail].  However, I prefer that bug reports be
  posted to my web site, so that they can be seen by others.

  6.2.  Low level PCMCIA debugging aids

  The PCMCIA modules contain a lot of conditionally-compiled debugging
  code.  Most of this code is under control of the PCMCIA_DEBUG
  preprocessor define.  If this is undefined, debugging code will not be
  compiled.  If set to 0, the code is compiled but inactive.  Larger
  numbers specify increasing levels of verbosity.  Each module built
  with PCMCIA_DEBUG defined will have an integer parameter, pc_debug,
  that controls the verbosity of its output.  This can be adjusted when
  the module is loaded, so output can be controlled on a per-module
  basis without recompiling.

  There are a few debugging tools in the debug_tools/ subdirectory of
  the PCMCIA distribution.  The dump_tcic and dump_i365 utilities
  generate complete register dumps of the PCMCIA controllers, and decode
  a lot of the register information.  They are most useful if you have
  access to a datasheet for the corresponding controller chip.  The
  dump_tuples utility lists a card's CIS (Card Information Structure),
  and decodes some of the important bits.  And the dump_cisreg utility
  displays a card's local configuration registers.

  The memory_cs memory card driver is also sometimes useful for
  debugging.  It can be bound to any PCMCIA card, and does not interfere
  with other drivers.  It can be used to directly access any card's
  attribute memory or common memory.

  6.3.  How do I write a Card Services driver for a new card?

  The Linux PCMCIA Programmer's Guide is the best documentation for the
  Linux PCMCIA interface.  The latest version is always available from
  hyper.stanford.edu in /pub/pcmcia/doc, or on the web at
  http://hyper.stanford.edu/HyperNews/get/pcmcia/home.html.

  For devices that are close relatives of normal ISA devices, you'll
  probably be able to use parts of existing Linux drivers.  In some
  cases, the biggest stumbling block will be modifying an existing
  driver so that it can handle adding and removing devices after boot
  time.  Of the current drivers, the memory card driver is the only
  ``self-contained'' driver that does not depend on other parts of the
  Linux kernel to do most of the dirty work.

  I've written a skeleton driver with lots of comments that explains a
  lot of how a driver communicates with Card Services; you'll find this
  in the PCMCIA source distribution in modules/skeleton.c.

  6.4.  Guidelines for PCMCIA client driver authors

  I have decided that it is not really feasible for me to distribute all
  PCMCIA client drivers as part of the PCMCIA package.  Each new driver
  makes the main package incrementally harder to maintain, and including
  a driver inevitably transfers some of the maintenance work from the
  driver author to me.  Instead, I will decide on a case by case basis
  whether or not to include contributed drivers, based on user demand as
  well as maintainability.  For drivers not included in the core
  package, I suggest that driver authors adopt the following scheme for
  packaging their drivers for distribution.

  Driver files should be arranged in the same directory scheme used in
  the PCMCIA source distribution, so that the driver can be unpacked on
  top of a complete PCMCIA source tree.  A driver should include source
  files (in ./modules/), a man page (in ./man/), and configuration files
  (in ./etc/).  The top level directory should also include a README
  file.

  The top-level directory should include a makefile, set up so that
  ``make -f ... all'' and ``make -f ... install'' compile the driver and
  install all appropriate files.  If this makefile is given an extension
  of .mk, then it will automatically be invoked by the top-level
  Makefile for the all and install targets.  Here is an example of how
  such a makefile could be constructed:

  # Sample Makefile for contributed client driver
  FILES = sample_cs.mk README.sample_cs \
          modules/sample_cs.c modules/sample_cs.h \
          etc/sample etc/sample.opts man/sample_cs.4
  all:
          $(MAKE) -C modules MODULES=sample_cs.o
  install:
          $(MAKE) -C modules install-modules MODULES=sample_cs.o
          $(MAKE) -C etc install-clients CLIENTS=sample
          $(MAKE) -C man install-man4 MAN4=sample_cs.4
  dist:
          tar czvf sample_cs.tar.gz $(FILES)

  This makefile uses install targets defined in 2.9.10 and later
  versions of the PCMCIA package.  This makefile also includes a
  ``dist'' target for the convenience of the driver author.  You would
  probably want to add a version number to the final package filename
  (for example, sample_cs-1.5.tar.gz).  A complete distribution could
  look like:

       sample_cs.mk
       README.sample_cs
       modules/sample_cs.c
       modules/sample_cs.h
       etc/sample
       etc/sample.opts
       man/sample_cs.4

  With this arrangement, when the contributed driver is unpacked, it
  becomes essentially part of the PCMCIA source tree.  It can make use
  of the PCMCIA header files, as well as the machinery for checking the
  user's system configuration, and automatic dependency checking, just
  like a ``normal'' client driver.

  I will accept client drivers prepared according to this specification
  and place them in the /pub/pcmcia/contrib directory on my FTP server,
  hyper.stanford.edu.  The README in this directory will describe how to
  unpack a contributed driver.

  The PCMCIA client driver interface has not changed much over time, and
  has almost always preserved backwards compatibility.  A client driver
  will not normally need to be updated for minor revisions in the main
  PCMCIA package.  I will try to notify authors of contributed drivers
  of changes that require updates to their drivers.

  6.5.  Guidelines for Linux distribution maintainers

  If your distribution has system configuration tools that you would
  like to be PCMCIA-aware, please use the *.opts files in /etc/pcmcia
  for your ``hooks.''  These files will not be modified if a user
  compiles and installs a new release of the PCMCIA package.  If you
  modify the main configuration scripts, then a fresh PCMCIA install
  will silently overwrite your custom scripts and break the connection
  with your configuration tools.  Contact me if you are not sure how to
  write an appropriate option script.

  When building PCMCIA for distribution, you should consider including
  contributed drivers that are not part of the main PCMCIA package.  For
  reasons of maintainability, I am trying to limit the core package
  size, by only adding new drivers if I think they are of particularly
  broad interest.  Other drivers will be distributed separately, as
  described in the previous section.  The split between integral and
  separate drivers is somewhat arbitrary and partly historical, and
  should not imply a difference in quality.