Random ocassional graphics freeze on Intel chipset

[Chris Wilson]

On Tue, Oct 01, 2013 at 06:15:00PM -0500, Alex Villací­s Lasso wrote:
> I have seen this graphics freeze under stock 3.10.x from the Fedora
> 18 x86_64 distro, and also with vanilla compiled 3.11 and 3.12-rc3.
> After a few hours of working, the screen stops updating. The mouse
> pointer moves around and changes if moved over different parts of
> the screen, but the display itself does not change anymore. If I
> check /sys/kernel/debug/dri/0/i915_error_state right then (via a
> remote ssh), there is no error captured. However, if I do "echo 1 >
> /sys/kernel/debug/dri/0/i915_wedged", after a few moments an error
> is captured, as well as messages in the kernel log, both of which
> are attached. If I try to restart the gnome-shell session, I get the
> KMS console, and then the start of the graphic login, but then the
> graphic login itself freezes again.
> 
> Is the attached information enough to diagnose the issue?

Afaict it was a userspace hang, the GPU was rightfully idle. Only on the
reset did it actually die.

I'd suggest looking at the stacktraces of the usual suspects and see who
is waiting upon whom, or if there is a more obvious lockup. Then begin
the painful process of tracing the interoperation of those two processes
to try and catch the breakdown.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre