X crash with radeon driver - AGP broken?

Vladimir Timofeev vovkasm at gmail.com
Sun Nov 25 09:24:02 PST 2007

On Nov 25, 2007 6:18 PM, Lionel Flandrin <simias.n at gmail.com> wrote:
> "Vladimir Timofeev" <vovkasm at gmail.com> writes:
> > Hi, if u have nforce2 chipset on motheboard side,
>   I do
> > try this patch...
> > with this I can run X, but not test more...
> >
> > How to patch:
> > cd /usr/src
> > patch < latest-agp_nvidia.c.diff
> >
> > my conf: Abit NF7 motheboard, Radeon 9200 video, fbsd 7.0-BETA3, X
> > Server 1.4.0 (from /var/log/Xorg.0.log)
> >
>   I have a zenith chaintech motherboard and a radeon 9600 pro, same
> fbsd/X version, and indeed, it works, thanks a lot! I can finally use my
> two screens again!
>   I played with xrandr, glxgears and some 3d apps (blender for instance)
> and it seems to work perfectly. Will this patch be commited to the main
> tree ?
May be, if this works and doing right things ;-) After some code
cleanup and revision... I'am not commiter anything... may be Eric

>   Also, I'm curious, what was the problem in the first place ? I must
> say I have no clue what this patch is doing (excepted it doesn't seem
> too nasty :).
Story of this patch is short. I take this kernel crash after upgrade
to current (now releng 7). May be gcc4 change 'volatile' behaviour or
anything else...
I start studing code differences in linux and fbsd agp drivers code.
In this patch for agp_nvidia_flush_tlb I realize two things:
1. get out volatile temporary variable to switch off potentialy
compiler optimizations (in linux code this variable absent)
2. ensure that we read no more than allocated entries in agp gatt
structure (in linux and current realization this read 33(magic?)
But it only my guesses. (I'am not c programmer, only know syntax ;-)

> Thanks again,
> --
> Lionel

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