[PATCH] Ensure blitter quiescience before reading pixels from the framebuffer
michel at tungstengraphics.com
Mon Jul 30 06:58:16 PDT 2007
On Mon, 2007-07-30 at 14:02 +0200, Bernardo Innocenti wrote:
> Michel Dänzer wrote:
> > Not sure there's still anyone around who cares about XAA...
> afaik, as of today XAA is still the default on all mayor Linux
> distros. Simple bug fixes are probably still wanted.
So are you volunteering to maintain XAA? :)
> >> Moreover, we're just scratching the surface of serious performance
> >> bottlenecks in both EXA and XAA. Is anyone interested in discussing
> >> possible solutions?
> > I certainly am for EXA.
> I'm unsure how we could eliminate those 1x1 pixmaps used for solid fills,
> but they're certainly a big performance hit. In some cases, we even upload
> them to the framebuffer by *dma*, then read the pixel with CPU :-)
Adam Jackson fixed that in GIT.
> A half-way solution would involve teaching the server-side to recognize these
> degenerate cases early and throw away the picture. This would still require
> changes in the interface between EXA and the drivers.
If there's still a measurable penalty in some cases with the above
change, this is probably the way to go.
Earthling Michel Dänzer | http://tungstengraphics.com
Libre software enthusiast | Debian, X and DRI developer
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