Re: Visual artifacts on radeon 9500 dri

Written by Alex Deucher on 03/16/08 19:55>>
> On Sun, Mar 16, 2008 at 8:49 PM, Reid Linnemann <[email protected]> wrote:
>> Jerome Glisse wrote:
>>  > On Sat, 15 Mar 2008 11:00:25 -0500
>>  > Reid Linnemann <[email protected]> wrote:
>>  >
>>  >> Hi list, this is my first time posting and I'm not subscribed.
>>  >>
>>  >> I'm running Xorg 7.3 with dri on FreeBSD 7-STABLE.
>>  >>
>>  >> Some time ago I noticed that seemingly random pixels were not being
>>  >> rendered in all GL contexts, and simply chalked it up to my card aging.
>>  >> But after a while it started to irk me, and then I remembered something
>>  >> about my sapphire 9500 - it's got one of the chips with 8 pipelines but
>>  >> only 4 enabled, presumably a 9700 that didn't pass QA and was rebadged
>>  >> as a 9500. At one time this card was on a Windows box, and I tried
>>  >> enabling all 8 pipelines with the softmod, and got the checkerboard
>>  >> pattern that indicated this.
>>  >>
>>  >> With this in mind, I took 10 dumps of a glxgears window and merged them
>>  >> together in a multilayer image in gimp, alternating multiply/divide, and
>>  >> overlaid a 16x16 grid. The artifacting lined up perfectly in the
>>  >> checkerboard pattern. I'm now pretty convinced that somehow either my
>>  >> system's DRM module, DRI, or radeon driver are erroneously enabling all
>>  >> 8 pipelines on the card, resulting in mooky-stink rendering. Anyone have
>>  >> any thoughts on this?
>>  >>
>>  >> I've attached the images with and without the overlaid grid for reference.
>>  >>
>>  >>
>>  >
>>  >>From memory code which detect card model and decide how many
>>  > pipe to enable is wrong for many card. We were just optimistic.
>>  >
>>  > Cheers,
>>  > Jerome Glisse <[email protected]>
>>
>>  I'd be fine if I knew what code initialized the pipelines, then I might
>>  be able to alter it to my needs.
>>
> 
> search for R300_GB_TILE_PIPE_COUNT in r300_state.c
> 
> Alex

FWIW I've tried changing the value of this constant from 3<<1 (or 6) to
2<<1 (or 4), but the bad tiles persist - only unrendered to. They just
appear as flickering holes in the gl context in the same checkerboard
pattern. Does that mean anything to you?

Thanks,
Reid

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