[PATCH] Ensure blitter quiescience before reading pixels from the framebuffer

Michel Dänzer michel at tungstengraphics.com
Mon Jul 30 10:02:45 PDT 2007

On Mon, 2007-07-30 at 18:13 +0200, René Rebe wrote:
> On Monday 30 July 2007 16:57:36 Michel Dänzer wrote:
> > On Mon, 2007-07-30 at 16:39 +0200, Bernardo Innocenti wrote:
> > > Michel Dänzer wrote:
> > > 
> > > I depend on XAA because EXA is still unusably slow on all hardware
> > > I ever tried it with.  I wonder if there's someone with a different experience.
> > 
> > I wouldn't bother spending effort on EXA if it didn't work better for
> > me. Probably you're not using a composited desktop?
> On xf86-video-intel 2.1.0 with Beryl / Emerald drawing everying, XAA is still way
> faster then EXA. Noticable - like 5x faster w/ EXA on a Core 2 Duo MacBook.
> On my girl's Sony Vaio with just a Core Duo @ 1.66 GHz the same Intel driver
> (just built for 32bit of course) is so slow, that it just draws 1fps with EXA when
> you scroll in kpdf, abiword etc. while with EXA it is usable, most of the time.

For a GLX compositing manager, you need zero-copy
GLX_EXT_texture_from_pixmap which is only available in the xserver GIT
master branch (and only with the Mesa GIT master branch driver i915tex
for this hardware so far).

> (Oh and yes, this is the intel driver with the XaaNoOffscreenPixmaps option as
> otherwise the composited desktop is not updated for whatever reason).

It's necessary due to bugs or at least severe design issues in XAA. It
essentially disables 2D acceleration with a compositing manager.

Earthling Michel Dänzer           |          http://tungstengraphics.com
Libre software enthusiast         |          Debian, X and DRI developer

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