drm/i915: Distinguish last emitted request from last submitted request
authorChris Wilson <chris@chris-wilson.co.uk>
Fri, 7 Oct 2016 06:53:24 +0000 (07:53 +0100)
committerChris Wilson <chris@chris-wilson.co.uk>
Fri, 7 Oct 2016 07:27:22 +0000 (08:27 +0100)
commit8687b3ec852e89630bac650f15136811c7b4c1dc
treeff72a72810fb382494450e46cd30a4a7eed02421
parent69a44b16cba895ff761c1763508c271a084950b5
drm/i915: Distinguish last emitted request from last submitted request

In order not to trigger hangcheck on a idle-but-waiting engine, we need
to distinguish between the pending request queue and the actual
execution queue. This is done later in "drm/i915: Enable multiple
timelines" but for now we need a temporary fix to prevent blaming the
wrong engine for a GPU hang.

(Note that this causes a temporary subtle change in how we decide when
to allow a waitboost to be re-awarded back to the waiter, the temporary
effect is that if the wait is upon the most current execution the wait
is given for free, instead of checking to see if the client stalled
itself. This will be repaired in "drm/i915: Enable multiple timelines".)

Fixes: 0a046a0e93d2 ("drm/i915: Nonblocking request submission")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98104
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161007065327.24515-1-chris@chris-wilson.co.uk
drivers/gpu/drm/i915/i915_gem_request.c
drivers/gpu/drm/i915/intel_ringbuffer.h