May have bricked my GPU

Michel Dänzer michel at
Mon Mar 26 06:05:11 PDT 2012

On Son, 2012-03-25 at 14:39 -0700, Connor Behan wrote: 
> I was working on adding EXA support to xf86-video-r128. I successfully 
> got as far as and I 
> still suggest that you accept this patch since it does not contain the 
> dangerous part. The dangerous part came when I tried to support 
> compositing as this needed some OUT_RING and OUTREG commands. I based 
> this on the KAA approach: 
> r128_composite.c. When I was finished, I ended up with an r128_exa.c 
> file that looked like this: Now I realize 
> that I may be asking a difficult question as many of you haven't worked 
> on this stuff for years, but here's how it went.
> I installed this new DDX and first tried to start the X server with EXA 
> and DRI but the composite extension turned off. Just to make sure that 
> everything that worked before still worked. However, it did not work. It 
> gave me this log file: showing the lines: 
> R128(0): R128CCEWaitForIdle: (DEBUG) CCE idle took i = 1025 and R128(0): 
> Idle timed out, resetting engine...

Note that as you can see in this log file, disabling the Composite
extension doesn't disable the EXA Composite acceleration hooks (which
can be disabled with Option "EXANoComposite"), which are used for RENDER
extension compositing operations (e.g. for rendering text). Though if
you're using a window manager which uses the Composite extension when
available, it might still have made a difference.

Earthling Michel Dänzer           |         
Libre software enthusiast         |          Debian, X and DRI developer

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