Catalyst 8.12 and Xorg 7.4

[cottrell]

I'm using Catalyst 8.12 on a Thinkpad T60, Linux 2.6.28.1.
I've been running Xorg 7.2 and everything has been playing
nicely. Today I updated to Xorg 7.4 and reinstalled Catalyst,
and now I'm seeing a few nasties, viz.,

* Artifacts in the form of narrow vertical black lines in
e.g. xterm and Nedit. These go away if I force a redraw
(shade and unshade the window).

* Crappy GL performance. For example with glxgears (and
also the GL xscreensaver modules). I get a high frame rate
OK, but it's like there are diagonal black bands passing
through the image.

Any ideas on whether this sort of thing can be fixed by
tweaking xorg.conf? My fglrx entry is pretty much vanilla.

[bridgman]

Are you running with a compositor (Compiz, Kwin, Metacity etc..) ? The GL bands sound a bit like what you get when a direct-rendered 3D app is fighting the compositor.

[cottrell]

Sorry, should have said: No, I'm not running a compositor,
just an oldish version of gnome 2 with the sawfish window
manager. Also I have in xorg.conf

Section "Extensions"
Option "Composite" "disable"
EndSection

Section "ServerFlags"
Option "AIGLX" "off"
EndSection

[bridgman]

OK, might just be the high frame rate "beating" with screen refresh. I think there is an option in the control panel to enable sync-to-vblank for OpenGL - can you check to see if that is turned on ?

Your glxgears framerate will probably drop to 60 fps but (everyone repeat after me) glxgears is not a good benchmark anyways ;)

[cottrell]

Sorry, I'm not finding the exact option you mention. Is this the
same as aticonfig --sync-vsync=on? I turned that on and restarted
the X server but it doesn't seem to make any difference. Possibly
relevant: I notice that the frame rate reported by glxgears under
Xorg 7.4 / ATi x740 is almost twice that reported with Xorg 7.2 /
ATi x710 (i.e. 7000+ vs. about 4000).

[bridgman]

Sorry, what is an x740 ?

I think there is a checkbox in the control panel for vsync. Not in front of my system right now though.

[cottrell]

By "x740" I mean the set of binary files in the ati installer
package under the directory named x740 (fglrx_drv.so and friends).

I'm not sure what you mean by "control panel": is this
amdcccle?

[bridgman]

Ahh. I was thinking an X740 GPU and it turned out some boards were actually shipped with an "X740" (which was news to me ;)).

Yes, amdcccle = AMD Catalyst Control Center Linux Edition aka control panel.

[cottrell]

Ah, OK. In amdcccle there's a config slider labeled
"Wait for vertical refresh" with a scale "Performance <->
Quality". Out of the box the slider was at the Performance
end, but I've moved it to Quality, which corresponds to

Option "Capabilities" "0x00000800"

in xorg.conf. I'm afraid this doesn't make a visible
difference to the GL performance.