[cairo] Image scaling performance on X

[Eric Anholt]

On Tue, 2007-02-27 at 03:30 -0500, Boris Zbarsky wrote:
> Eric Anholt wrote:
> > Much of Render can't be accelerated with XAA, which is what most 2d
> > drivers use, resulting in awful performance.  We've been working on EXA
> > to replace XAA, and I'm using it daily now, but most drivers still need
> > some more love before EXA can be flipped to be the default on them.
> 
> Eric, that sounds wonderful, but if I understand correctly that's the plan going 
> forward, right?  It won't apply to the existing install base?
> 
> The problem is that shipping a Cairo-based Gecko sometime in 2007 requires a 
> solution that works with existing X installs....
> 
> If I'm misunderstanding and there are plans to backport EXA to what are 
> currently stable releases of distros, that's great!
> 
> Is there any way to detect from inside Cairo whether EXA or XAA is used and fall 
> back on something other than Render as needed?

The 1.3 X Server, which we'll be releasing soon, will have sufficiently
new EXA.  Then it's just up to drivers to support it.  However, like
OpenGL, we won't be providing any information as to whether specific
paths are hardware accelerated or not (due to the answer usually being
"maybe" or "I don't know yet").  It's up to applications that care to do
timings and find alternative methods if Render performance isn't up to
their needs.

The intel driver has pretty decent Render acceleration now, and
hopefully Radeon's bugs are gone with some of the recent bugfixing we've
done in EXA.  That leaves nv for major drivers without EXA support, but
I understand the nouveau guys are working on it.

-- 
Eric Anholt                             anholt at FreeBSD.org
eric at anholt.net                         eric.anholt at intel.com

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