drm/i915: Fix pages pin counting around swizzle quirk
authorChris Wilson <chris@chris-wilson.co.uk>
Fri, 4 Nov 2016 10:30:01 +0000 (10:30 +0000)
committerChris Wilson <chris@chris-wilson.co.uk>
Fri, 4 Nov 2016 11:55:39 +0000 (11:55 +0000)
commit2c3a3f44dc13a7c964e93385e1c1ca848656bed0
treedcc94f3bc020903a2aebfb4d56106623741525cb
parenta44342acde304425fa70fd4f06c0e662a79ba5aa
drm/i915: Fix pages pin counting around swizzle quirk

commit bc0629a76726 ("drm/i915: Track pages pinned due to swizzling
quirk") fixed one problem, but revealed a whole lot more. The root cause
of the pin count mismatch for the swizzle quirk (for L-shaped memory on
gen3/4) was that we were incrementing the pages_pin_count upon getting
the backing pages but then overwriting the pages_pin_count to set it to
1 afterwards. With a little bit of adjustment to satisfy the GEM_BUG_ON
sanitychecks, the fix is to replace the explicit atomic_set with an
atomic_inc.

v2: Consistently use atomics (not mix atomics and helpers) within the
lowlevel get_pages routines. This makes the atomic operations much
clearer.

Fixes: 1233e2db199d ("drm/i915: Move object backing storage manipulation")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161104103001.27643-1-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
drivers/gpu/drm/i915/i915_gem.c
drivers/gpu/drm/i915/i915_gem_gtt.c
drivers/gpu/drm/i915/i915_gem_tiling.c