X crashes when logging off (Kubuntu gutsy, fglrx 8.41.7)

[TQ]

Binary package hint: xserver-xorg

This is a Toshiba A200 1GB laptop. The graphics card is an ATI Mobility HD 2600 and I'm running the ATI fglrx driver, version 8.41.7 (since nothing else works with this card except vesa, which can't give me the native resolution ;)). I'm running Kubuntu gutsy.

When logging off from the K Menu, X crashes. This means I'm left at the tty1 login prompt, with the mouse cursor still painted on screen. Upon login, inspection of /var/log/Xorg.0.log reveals:

==========
Backtrace:
0: /usr/bin/X(xf86SigHandler+0x81) [0x80c9561]
1: [0xffffe420]
2: /usr/lib/xorg/modules/extensions//libGLcore.so(_mesa_free+0x1d) [0xb14a87ad]
3: /usr/lib/xorg/modules/extensions//libGLcore.so(XMesaDestroyVisual+0x1d) [0xb15a199d]
4: /usr/lib/xorg/modules/extensions//libGLcore.so [0xb15a118f]
5: /usr/lib/xorg/modules/extensions//libglx.so(__glXResetScreens+0x37) [0xb7c116c7]
6: /usr/lib/xorg/modules/extensions//libglx.so [0xb7c1086c]
7: /usr/bin/X(CloseDownExtensions+0x46) [0x809c636]
8: /usr/bin/X(main+0x4af) [0x8076eff]
9: /lib/tls/i686/cmov/libc.so.6(__libc_start_main+0xe0) [0xb7d8b050]
10: /usr/bin/X(FontFileCompleteXLFD+0x1e9) [0x8076221]

Fatal server error:
Caught signal 11. Server aborting
==========

So I do a `ps -A` and see kdm still running. I do Ctrl+Alt+F7 to see if the login screen is there and the display freezes blank. I can't type anything nor switch back to another tty. The only thing I can do is restart via the power button (Ctrl+Alt+Del no luck).

I reboot, login and logoff again. This time when I get at the tty1 prompt I try switching to another tty < 7, and back again. That works. I do a `sudo killall kdm`, then `sudo /etc/init.d/kdm restart`. I get back at the login screen, everything normal.

Please tell me what else I should report. I'm aware that the ATI driver is unsupported; does that mean I'm not entitled to report the the problem on Launchpad?