Xorg eats CPU when using EXA

I confirm this. It makes GNOME feel slow in general, and is very noticeable in some particular cases - for example, open Nautilus, grab its lower right corner, and try resizing the window for several seconds. It's extremely slow to repaint. Switching back to XAA makes it very fast again.

My configuration is similar to that of the OP:
  Ubuntu Intrepid, fully updated as of 2008-09-13
  ATI Mobility Radeon 9700 (X300)
  Radeon driver 1:6.9.0+git20080826.a3cc1d7a-2ubuntu2

I haven't messed with the default xorg.conf, other than switching EXA on. Glxgears is accelerated, and direct rendering is on.

Note that using the same driver on Hardy (taken from Tormod Volden's PPA), I didn't have this problem with EXA. Also, I'm not using Compiz.

Still not fixed, and I consider this bug quite severe as user wanting to playback video's with compiz enabled will experience it. I'm milestoning it for the final release, please undo if it isn't worth it :)

I'm experiencing this bug since the xserver video driver updates around 12/09. xorg-xserver-video-ati got updated then with the changelog:
* Rebuild against the new xserver-xorg-dev.
Shouldn't cause this problems, though?

I'll upload a verbose glxinfo with both accelerators soon.

Verbose glxinfo does not differ between EXA and XAA.

Just removed xserver-xorg-video-radeon et al and pulled a GIT copy to try to locate the commit which introduced the bug.
I reverted all the way to june 2008, but the EXA lags keeps happening. As I worked with a non-lagging EXA using the xserver-xorg-video-radeon-git20080802, I guess the EXA lag is NOT caused by xorg-video-radeon.....

Any hints how to locate this bug?

I asked for information at the #radeon channel, which turned up that it's a bug of Xorg itself:
http://lists.freedesktop.org/archives/xorg/2008-September/038534.html

There was also said that Xserver 1.5.1 (or probably 1.5.2) will contain a fix for that EXA problem. IMHO it'll be one of the more important patches which'll have to be packed into Ibex, even if it will already have been released by then.

Status of this bug updated to match most recent information.

This bug was fixed in the package xorg-server - 2:1.5.1-1ubuntu1

---------------
xorg-server (2:1.5.1-1ubuntu1) intrepid; urgency=low

  * Merge with Debian experimental. (LP: #269388)

xorg-server (2:1.5.1-1) experimental; urgency=low

  * New upstream bugfix release.
  * 02_Disable-DRI-in-Xephyr.patch: don't use DRI in Xephyr, as it doesn't
    work correctly.
  * Merge changelog from 2:1.4.2-6 (all changes are upstream now).

 -- Timo Aaltonen <email address hidden> Wed, 24 Sep 2008 19:33:34 +0300

Confirmed, thanks a lot all!