drm/i915: Provide a timeout to i915_gem_wait_for_idle() on setup
authorChris Wilson <chris@chris-wilson.co.uk>
Mon, 9 Jul 2018 12:20:43 +0000 (13:20 +0100)
committerChris Wilson <chris@chris-wilson.co.uk>
Mon, 9 Jul 2018 12:56:42 +0000 (13:56 +0100)
commit2621cefaa42b3a7455d30e78831c6b55290d40c8
treed5d7b69cd7441d061af741c0f0a8a265d531a9ba
parentec625fb932bb057e2d3c2ed28eee56a827385ab8
drm/i915: Provide a timeout to i915_gem_wait_for_idle() on setup

With a broken GPU we expect it to fail during the initial
GPU setup where do a couple of context switches to record the defaults.
This is a task that takes a few milliseconds even on the slowest of
devices, but we may have to wait 60s for hangcheck to give in and
declare the machine inoperable. In this a case where any gpu hang is
unacceptable, both from a timeliness and practical standpoint.

We can therefore set a timeout on our wait-for-idle that is shorter than
the hangcheck (which may be up to 60s for a declaring a wedged driver)
and so detect the broken GPU much more quickly during driver load (and
so prevent stalling userspace for ages).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180709122044.7028-2-chris@chris-wilson.co.uk
drivers/gpu/drm/i915/i915_gem.c