NetNews Usenet Archive 1992 #19/NN_1992_19.iso/spool/comp/os/linux/9157

Internet Message Format | 1992-08-26 | 1.3 KB

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From: [e-mail] (Chris Laurel)
Newsgroups: comp.os.linux
Subject: I/O protection level
Message-ID: <[e-mail]>
Date: 26 Aug 92 18:32:27 GMT
Sender: [e-mail]
Organization: LaserMaster R&D, Minneapolis, MN  USA
Lines: 18
Nntp-Posting-Host: chrisl.lmt.com

I want play around with the enhanced features of my Fahrenheit 1280
video board (S3-based), but in order to do this I need to be able to access
portsabove 0x3ff.  Ports above 0x3ff are not mapped by Linux into the per-
process IO bitmap, so I cannot use the ioperm system call.  I looked through
the Linux source code and saw code for an 'iopl' system call, but I was
unable to get this to work (Linux 0.97)--the call was not present in the C
libraries.  Could someone tell me how to use the iopl system call?  Or
inform me of another method to access high ports?  I presume that writing an
assembly language routine to set the iopl directly by pushing/popping the
flags register will not work if it is executed by a user process . . .

Also, does anyone have any S3 hacks for linux that they would be willing to
share?

Thanks,

Chris Laurel
[e-mail]