[Sderby] suse 8.2 pro crashing

[Harry Sheppard]

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Hello,

> I have had a look at the VAR/LOG/WARN file and the same warnings seem to
> occur prior to a crash. These are:
> linux modprobe: modprobe: Can't locate module fb1
> linux modprobe: modprobe: Can't locate module fb2
> linux kernel:mtrr: 0xc0000000, 0x4000000 overlaps existing
> 0xc0000000,0xc2000000

<Skip to the end to see solutions!>

This whole thing looks graphics related (see previous post - AGP bit). modules
fb1 and fb2 are framebuffer devices - it looks like its trying to load more
than one instance of the module (first framebuffer device is generally fb0)
and in doing so is overwriting the tail end of the existing framebuffer's
memory transfer range. (MTRR = Memory Transfer Range Register).

<TECH>
AMD machines also have a problem with the way they work with memory. The newer
Palomino and Barton cores employ rather agressive memory prefetch routines
that allow the CPU to read data in from main memory just in case it needs it.
If there is a prefetch miss and the CPU pipeline stalls, this unused data is
flushed from cache and written back to RAM. However, if that data was
changed, that changed data would be 'reset' by the processor's cache-commit
cycle, hence system memory loosing coherence and causing a system to crash.
The way the linux framebuffer device works tends to invoke quite a few of
these prefetch routines and, without a suitable kernel patch to the Graphics
Address Remapping Table (GART) section of the code, the framebuffer and / or
graphics aperture addresses can become scrambled as main memory and the
processor cache loose coherence.
The full techie explanation can be found here::
http://www.geocrawler.com/lists/3/Linux/35/175/7626960
</TECH>

The above problems are totally Linux specific, hence the machine behaving
under XP.

There's no quick fix other than updating your kernel (and probably X as well).

Probable solutions::
The easy way - get a later SuSE distribution as suggested by someone earlier.
SuSE 9 has all of the AMD / GART fixes applied.
The not-so-easy way - upgrade your kernel and XFree86 packages yourself,
either by using YaST (YaST Online Update should be able to hoover the latest
packages from the SuSE FTP site for you), RPM or compiling from source (not
particularly advisible if you haven't done it before).

Hope that helps,
- --Harry Sheppard
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