drm/i915: Be paranoid and post the writes to stop the rings

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Although the mmio are uncached and so should be flushed on every write,
be paranoid and do a mmio read after setting the ring head/tail to be
sure they have taken effect before moving on.

v2: post tail to be pleasing to the eye

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180208072800.595-1-chris@chris-wilson.co.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>

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Chris Wilson 2018-02-08 07:28:00 +00:00

parent 0d73e7a095

commit bc8f2f5db9

1 changed files with 2 additions and 0 deletions

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drivers/gpu/drm/i915/intel_uncore.c

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