S.u.S.E. Support Data Base

Title: Adaptec 2940 (aic7870, aic7880) onboard controller

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Adaptec 2940 (aic7870, aic7880) onboard controller

Symptoms:

The 2940 driver (aic7xxx) does not find the onboard SCSI controller at boot time. If the onboard SCSI controller is the only one, the corresponding line in the bootmessages resembles:
scsi : 0 host. 
The SCSI device connected to the controller could not be found.

Some mainboards reveal a strange situation. It could happen that the onboard SCSI controller was found whereas the SCSI devices are not found.

Cause:

Linux exactly follows the PCI guidelines. There are indeed some mainboards whose PC-BIOS does not follow these standards. Among the obvious ones are some PCI systems from Compaq. This is why the kernel driver can not find the onboard controller in such systems.

On other systems it might occur that although the onboard controller was found it is not possible to access the SCSI devices. In this case the reason is that the onboard controller's interrupt is switched off while reading the defectuous PCI-BIOS, and afterwards it cannot be switched on again by the kernel. Consequently the onboard controller's interrupt is switched off at the first SCSI access to the SCSI devices, and the devices cannot be detected.

Solution:

You can correct this by using the Compaq program MOVEPCI. Ask your local dealer for it or try: ftp://ftp.compaq.com/pub/softpaq/ .

If you have a system which certainly finds the onboard SCSI controller but the SCSI devices are not detected, you should update your mainboard's BIOS. Another possibility is a patch that reads the PCI-BIOS with interrupts already switched off: ftp://ftp.suse.de/pub/special/bios32.c.diff.gz . This patch can be applied to a 2.0.xx kernel by invoking the following commands:

  cp bios32.c.diff.gz /usr/src/
  cd /usr/src/
  zcat bios32.c.diff.gz | patch -p0
Of course you have to recompile the kernel afterwards and install it. You may use this patch at your own risk. For your system's stability concerning data security it is recommended to update your mainboard's BIOS now!.

Hint:

There is an interesting page for compaq systems on the World Wide Web (WWW):

http://www-c724.uibk.ac.at/XL/

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See also:

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Keywords: PCIBIOS_INIT, PCI, BIOS, COMPAQ, COMPAC, ADAPTEC, 2940, AIC7870, AIC7880

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Feedback welcome: Send Mail to werner@suse.de (Please give the following subject: SDB-compaq)

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