[Bug 328528] Re: [i865G] UXA locks up system (UXA bug)

[Tomasz Czapiewski]

I've done some testing on i865G and I found that Xorg locks up with UXA (enabled manually by Option "AccelMethod" "UXA" in xorg.conf) when "drm" and "i830" kernel modules are not loaded - they are not loaded at startup time. It's strange that DRI is disabled by Xorg [(**) intel(0): DRI is disabled because it fails to run on 845G and 865G chips. (See LP 304871)] - even when passing Option "DRI" "true" to xorg.conf.
I've booted todays kubuntu jaunty i386 cd with EXA enabled by default on this chipset, then stoped KDM (checked in process list that "X" is not running - "ps aux | grep X"), then added 'Option "AccelMethod" "UXA"' in Device section in /etc/X11/xorg.conf. Next I've done 'sudo modprobe i830' in console so it loaded 'drm' and 'i830' modules - /dev/dri/card0 has appeared, then started pure Xorg by 'sudo X' - Xorg has run without problems (black screen but I suppose it's ok because on EXA and XAA have the same. Then I've installed 'xterm' and run 'DISPLAY=:0.0 xterm' as root on other console - then xterm connected but right after lost it's connection to xserver.

Then I saw that Xorg started from console showed this (just after the xterm tried to connect to X):
X: ../../src/i830_batchbuffer.h:78: intel_batch_emit_dword: Assertion `pI830->batch_ptr != ((void *)0)' failed.
(and core dumped, but I didn't found that core file by "find / -iname '*core*'" that would be core dump)

I'm attaching Xorg.0.log with that UXA start, too but I can't see errors
there.

Then I've tried to modprobe and rmmod intel drm modules - insert i810 module (no error but no dri device), removing all drm modules - i830, i810 and drm - dri device in /dev/dri/card0 has disappeared and modules have unloaded (double checked by "lsmod | less" and "lsmod | grep i8", "lsmod | grep drm").
Then I've started X just the same way as before - it have not crashed or locked, connected xterm - then it has crashed with just the same error.

I've repeated the whole procedure 3 times (with rebooting cd) and always the same results - X locks up system with UXA when no drm modules loaded, but crashes X (when connecting xterm or other X apps) when drm kernel modules for this chipset are loaded - since then it crashes (not locks up) even when I unload kernel modues until I reboot and start once more from the same cd.
Kernel drm modules does not change anything with EXA or XAA - I've checked that, too. It could change somthing if DRI could be enabled at Xorg startup.

Maybe there were other modules than 'drm' and 'i830' which where loaded
by 'modprobe i830' and I've should done diff from 'lsmod' before and
after modprobe but I haven't thought about it then and I've didn't do it
and now I don't have access to that hardware and probably wont have
access to it until RC or stable release of Jaunty.

Can anyone confirm that?


** Attachment added: "Xorg.0.log with UXA on i865G with i830 kernel module loaded and xterm trying to connect to X locally"
   http://launchpadlibrarian.net/24708962/Xorg.0.log

-- 
[i865G] UXA locks up system (UXA bug)
https://bugs.launchpad.net/bugs/328528
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.

-- 
ubuntu-bugs mailing list
ubuntu-bugs at lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs