intel 2.6.0: EXA choppy, UXA has artifacts

[Khashayar Naderehvandi]

On Sat, Jan 17, 2009 at 10:57 PM, Peter Clifton <pcjc2 at cam.ac.uk> wrote:
> On Sat, 2009-01-17 at 18:48 +0100, Khashayar Naderehvandi wrote:
>> Hi!
>>
>> I'm trying out the newly released intel driver on a X4500 chipset.
>> The stack is composed of:
>>
>> * kernel 2.6.28 with the patches from
>> http://intellinuxgraphics.org/2008Q4.html applied
>> * libdrm 2.4.4
>> * mesa 7.3rc1
>> * xorg-server 1.5.99.901.
>> * intel driver 2.6.0
>>
>> With EXA compiz becomes unusably choppy and slow. I don't know how to
>> explain the behavior in a good way, but it's like everything is run
>> through a stroboscope. Sort of.
>> With UXA, on the other hand, everything's smooth and nice, but there
>> are certain artifacts. Like this:
>> http://dl.getdropbox.com/u/175461/uxa-artifacts.png.
>>
>> Are these issues known? Any workarounds?
>
> The screen-saver you're previewing probably uses GL. Sounds like there
> is a chance you've not got DRI2 working properly?
>
> I've got a similar setup to you, and UXA is working nicely. (Just turn
> sync to vblank off in Compiz if you want framerate > 1/3 fps!)
>
> Check the Xorg.0.log to see if DRI2 is enabled.
>

DRI2 definitely seems to be working well:
khashayar at dionysos ~ $ cat /var/log/Xorg.0.log | grep -i dri2
(II) LoadModule: "dri2"
(II) Loading /usr/lib/xorg/modules/extensions//libdri2.so
(II) Module dri2: vendor="X.Org Foundation"
(II) Loading extension DRI2
(II) intel(0): [DRI2] Setup complete
(II) intel(0): direct rendering: DRI2 Enabled
(II) GLX: Initialized DRI2 GL provider for screen 0

Sync to VBlank is off.

I've noticed that the artifacts come from translucency effects. If you
look at the screenshot I linked to, all those windows have some
translucency to them.

I don't understand the part about the screen saver, though.

Thanks for commenting!
Khashayar


> --
> Peter Clifton
>
> Electrical Engineering Division,
> Engineering Department,
> University of Cambridge,
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>
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>
>