Bug#484180: mesa: some ASM optimizations must be disabled for non-AMD 64-bit

[Tormod Volden <debian.tormod@gmail.com>]

Package: mesa
Severity: normal
Tags: patch


This was reported in Ubuntu https://bugs.launchpad.net/bugs/87661 and I 
don't have the hardware to reproduce it, but I think this will be the 
same in Debian:

The ASM optimizations on mesa 64-bit builds include instructions (like 
for instance 3dnow) that are not available on Intel 64-bit processors, 
and hence some GL applications crash with SIGILL.

The proposed patch, in form of a Xsession.d script, sets the MESA_NO_ASM 
flag when 64-bit mesa is detected on a processor not having support for 
3dnow instructions.

-- System Information:
Debian Release: lenny/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: i386 (i686)

Kernel: Linux 2.6.25-2-486
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

:
# /etc/X11/Xsession.d/65mesa-check-x86-64

# This file is sourced by Xsession(5), not executed.

# If we are running the 64-bit mesa code, we need to disable ASM
# optimizations if we are on a non-AMD processor without 3dnow instructions
# (until this get fixed in the mesa libraries)

if [ `dpkg --print-architecture` = "amd64" ] &&
   ! grep -q "^flags.*3dnow" /proc/cpuinfo
then
      MESA_NO_ASM=1
      export MESA_NO_ASM
fi