drm/i915: dump even more into the error_state
authorDaniel Vetter <daniel.vetter@ffwll.ch>
Wed, 1 Feb 2012 21:26:45 +0000 (22:26 +0100)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Thu, 9 Feb 2012 14:50:23 +0000 (15:50 +0100)
commit7e3b8737e719c4de7dd79b096b80ece444b2f0ba
treef27d7ec762f899ab05f99018536a1a1677997bb4
parentff240199b6a3b0bec5ae9b6d26403dad38e8cb19
drm/i915: dump even more into the error_state

Chris Wilson and me have again stared at funny error states and it's
been pretty clear from the start that something was seriously amiss.
The seqnos last seen by the cpu were a few hundred behind those that
the gpu could have possibly emitted last before it died ...

Chris now tracked it down (hopefully, definit verdict's still out),
but in hindsight we'd have found the bug by simply dumping the cpu
side tracking of the ring head and tail registers.

Fix this and prevent an identical time-waster in the future.

Because the hangs always involved semaphores in one way or another,
we've tried to dump the mbox registers, but couldn't find any
inconsistencies. Still, dump them too.

Reviewed-and-wanted-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drivers/gpu/drm/i915/i915_debugfs.c
drivers/gpu/drm/i915/i915_drv.h
drivers/gpu/drm/i915/i915_irq.c