ATI Radeon R100 QD (7200) refuses to work with Compiz (Kernel 2.6.34-rc4)

[Michel Dänzer]

On Son, 2010-04-25 at 20:31 +1000, Dave Airlie wrote: 
> 2010/4/25 Michel Dänzer <michel at daenzer.net>:
> > On Son, 2010-04-25 at 11:35 +0200, Uwe Bugla wrote:
> >> Am Samstag, den 24.04.2010, 12:31 -0400 schrieb Alex Deucher:
> >> > On Sat, Apr 24, 2010 at 11:48 AM, Chicken Shack <chicken.shack at gmx.de> wrote:
> >> > >
> >> > > 1. The real issue of that Compiz problem IS NOT what dmesg says.
> >> > >
> >> > > The real issue of my problem is that the FIRST patch Dave Airlie
> >> > > attached for resolving this Compiz issue NEVER reached kernel mainline
> >> > > while the second one did obviously.
> >> > >
> >> > > So PLEASE do push up Dave's FIRST patch titled "fallback on VRAM memory
> >> > > placement" as fast as possible so that it becomes part of the kernel
> >> > > mainline!
> >> >
> >> > The first patch caused problems on some AGP systems due to the
> >> > unreliability of AGP so it wasn't pushed to mainline.  It should be
> >> > safe to push once this patch hits mainline:
> >> > http://git.kernel.org/?p=linux/kernel/git/airlied/drm-2.6.git;a=commit;h=61cf059325a30995a78c5001db2ed2a8ab1d4c36
> >
> > No, there were more issues with the patch[0] and it can't be pushed
> > again as is. A different approach will be needed to make things work
> > better on VRAM-limited systems.
> >
> >
> > [0] At least making pinning of BOs to VRAM unreliable, potentially
> > causing problems with BOs used by the display hardware (e.g. trying to
> > start a second X server when VRAM is full of BOs), and degrading
> > performance on systems where things work without the patch.
> 
> Yeah I'm going to try and fix that up this week now we fixed the AGP.
> 
> I'm just going to separate the pinning code from the validate code wrt
> domain->placement translation.

That's a start, but IME validation using the new scheme degrades
performance on setups which work with the old scheme. Maybe the old
scheme can be tried first and the new one as a fallback, at least as an
interim solution. But I think the new scheme really shouldn't be
necessary if we didn't over-report the amount of VRAM available to
userspace and prevented fragmentation due to pinned BOs, which should be
feasible.


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