Bug#392915: xserver-xorg-video-ati: xserver freezes system when starting

Michel Dänzer daenzer at debian.org
Thu Jan 11 00:37:26 PST 2007

# See also bug 403871
reassign 392915 linux-2.6
tags 392915 upstream fixed-upstream patch

On Wed, 2007-01-10 at 23:35 +0100, Andreas Johansson wrote:
> On Wed, Jan 10, 2007 at 10:15:15AM +0100, Michel Dänzer wrote:
> > Thanks. I think this is another integer overflow bug in the radeon DRM;
> > can you try the attached patch?
> Yes, this enables me to use a 32MB AGP aperture setting in the BIOS.
> Thanks for finding the cause of this problem!
> I used the Debian package linux-source-2.6.18 version 2.6.18-7 and
> patched drivers/char/drm/radeon_cp.c with your patch. Just radeon.ko
> was built, and installed manually. The rest of the kernel package
> remained as-is, I didn't build a complete package.
> Attached is the dmesg from my system using the resulting radeon.ko.
> I guess this is the interesting change:
> [drm] Can't use AGP base @0xfc000000, won't fit

Indeed, thanks for testing. Reassigning to the kernel, I pushed the fix
to drm git in


Alex: Looking at your Xorg.patched.log again, I'm afraid this won't fix
that case; it looks like MC_FB_LOCATION is set up to cover the whole 32
bit address space when the X server starts, and because the radeon
driver preserves this register with Option "UseFBDev" (maybe we should
change this, Ben?), the AGP aperture has to overlap the framebuffer.
This could be at least partly considered a bug in radeonfb (or even the
video BIOS?).

Earthling Michel Dänzer           |          http://tungstengraphics.com
Libre software enthusiast         |          Debian, X and DRI developer

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