[Intel-gfx] Page flipping not working as expected for compositing - engineering resource available to help fix it

[Simon Farnsworth]

On Monday 10 May 2010, Simon Farnsworth <simon.farnsworth at onelan.com> wrote:
> On Friday 7 May 2010, Simon Farnsworth <simon.farnsworth at onelan.com> wrote:
> > I've attached my test program (it's based on our C++ OpenGL compositor,
> > but cut down to just test OpenGL pageflipping) as performance.c, and my
> > test X stack's Xorg.0.log after one run of "performance -indirect"
> > (which ran for 573 frames). I'm using a 32-bit PAE kernel - I can add
> > information as required, and I'm happy to run tests or experiments for
> > people.
> > 
> > 2) How should I go about fixing compositing? Should I fix indirect
> > rendering to use pageflipping (and if so, where do I start looking for
> > the code that's getting it wrong), or should I make TFP work when direct
> > rendering (and again, where should I start looking)?
> 
> Is this the expected behaviour when indirect rendering? If so, I'll dive
> back into the stack and see if I can work out why TFP and direct rendering
> don't interact nicely. If not, roughly where should I look to fix it?

I've found why direct rendering and TFP don't interact nicely, and it's a 
client side error.

Briefly, my compositor was being started as our signage user, who does not have 
access to /dev/dri/card0, so was falling back to swrast. When you're using 
swrast, TFP only appears to work for pixmaps you create, not for compositing 
pixmaps.

Sorry for the noise,
-- 
Simon Farnsworth
Software Engineer
ONELAN Limited
http://www.onelan.com/