XGL/Compiz: Hack against compiz to suppress pixmap corruption and improve performance

[Francesco Biscani]

On Friday 03 March 2006 16:41, Erik Andrén wrote:
> Hi all.
> I've hacked up a small patch consisting of a pair of glFlush() calls in
> paint.c of Compiz.

Erik,

you made my day :)

> This resolves my problem of corrupt textures and increases performance
> quite a bit using a radeon 7500 mobility (r100).
> See the attached screenshot for how my display looked before.

This has solved for me some corruptions too. Before applying the patch I had 
some kind of "chessboard" effect, with some black squares covering the 
windows. Now the black squares are gone but often the windows, after I move 
them, disappear into oblivion. If I move them again (or zoom, or rotate the 
desktop or some other random interaction) they reappear briefly.

But... geez! The performance here really skyrocketed :) It may not be a huge 
difference if you have an high-end card, but on my Radeon IGP 345 it's like 
night and day. For example, moving around a fullscreen (1024x768) firefox 
window is now _very_ smooth, and CPU utilization is around 20%. Much better 
than moving around windows in XAA or EXA ;)

Now, if only you could find another Q&D hack for those disappearing windows I 
would be a very happy guy :)

Kudos Erik.

> I know that this isn't the long term solution but I figured that someone
> might want a quick-and-dirty (tm) fix.
>
> Take care
> Erik Andrén

Best regards,

  Francesco

-- 
Dr. Francesco Biscani
Dipartimento di Astronomia
Università di Padova
biscani at pd.astro.it