Radeon 7500 + Tseng ET6000 dual head lockups

Hi,

I have a dual head setup with ATI Radeon 7500 (AGP) and Tseng ET6000 
(PCI) cards. Everything (DRI on ATI, v4l on either display) works great 
(I'm not using Xinerama, but separate sessions). However, the computer 
locks hard from time to time (might be OK for several days, might crash 
several times a day). Once it happens, the computer is totally dead. 
Alt-SysRq-combinations do not work. On the other hand, if XawTV is on 
when the lockup occurs, the TV continues to show (IIRC), so at least the 
PCI bus and the display cards seem to survive the crash.

I haven't been able to note any common cause for the crashes. They 
happen both when I'm using the computer, and also when it's idling. It 
might be that some lockups have occurred when I touch the mouse, but I'm 
not sure if that's just a coincidence. Anyway, if I disable the 
dual-head setup (by commenting out the Tseng in ServerLayout), the 
computer becomes rock-solid, so the crashes are related to XFree86 somehow.

Oh, and I'm using Mandrake 9.0 flavour of XFree86, if that counts.

My config and log files are available at

http://mairas.net/tmp/X11-crashes/XFree86.0.log
http://mairas.net/tmp/X11-crashes/XF86Config-4

I'd appreciate any help or suggestions.

Best Regards,

Matti Airas