Re: [BUG] r200 dri driver deadlocks

[Dave Airlie <airlied@linux.ie>]

Can you insmod the radeon drm module with drm_opts=debug do the test and
send on the trace, it may be getting wedged somewhere unexpected...

Dave.

>
> All of this was tested with a virgin 2.6.8.1 (with debug info and
> frame pointers enabled) and Debian's XFree86 4.3.0.1, using DarkPlaces
> and Twilight (both popular quakeGL engine forks) as test apps, unless
> otherwise noted.
>
> Thanks to wli (who I owe at least one beer for this, may be an entire
> case), we've been able to figure exactly whats going on. The driver is
> turning off interrupts, then deadlocking. (No sysrq, no sshing in,
> capslock's light doesn't work.)
>
> Turning the NMI watchdog on, it 'fixes' the deadlock (and thanks to
> the watchdog, ssh and sysrq now work, but capslock's light still
> doesn't work), but the app and X are still dead, but now I can ssh in
> and kill -9 them both,  however, and quite obviously, I can't start
> another X, but I can reboot cleanly.
>
> Things already tested that don't effect bug:
> Turning SMP on or off
> Turning 4k stacks on or off
> Using new radeon fbcon, using old radeon fbcon, using no fbcon
> Turning Local APIC for uniproc and/or IO-APIC for uniproc on or off
> Turning preempt on or off
> Using mem=nopentium
> Waving a dead chicken over the box
>
> Things already tested for:
> Kernels as far back as 2.6.0 have this bug, haven't tested any earlier
>
> Thanks to netconsole (who I recommend to anyone that can't setup
> serial console stuff), I was able to capture the entire kernel output,
> including sysrq-t output right after my test app crashes.
>
> I'm including both the netconsole output and the .config. vmlinux and
> radeon.ko (and anything else you need) are available upon request.
>
>

-- 
David Airlie, Software Engineer
http://www.skynet.ie/~airlied / airlied at skynet.ie
pam_smb / Linux DECstation / Linux VAX / ILUG person