diff options
| author | Chris Wilson <chris@chris-wilson.co.uk> | 2018-02-08 07:28:00 +0000 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2018-02-08 13:43:14 +0000 |
| commit | bc8f2f5db9d75e7f990fb8362c28a8d2a7f33c9c (patch) | |
| tree | e9756a536bba72c68bffb8b8fb4d51faa8f72802 | |
| parent | 0d73e7a095f768fad5a002bf6732c675e2aee44b (diff) | |
drm/i915: Be paranoid and post the writes to stop the rings
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>
| -rw-r--r-- | drivers/gpu/drm/i915/intel_uncore.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c index 4075010ac088..db441bf3b9d5 100644 --- a/drivers/gpu/drm/i915/intel_uncore.c +++ b/drivers/gpu/drm/i915/intel_uncore.c @@ -1522,9 +1522,11 @@ static void gen3_stop_engine(struct intel_engine_cs *engine) engine->name); I915_WRITE_FW(RING_HEAD(base), I915_READ_FW(RING_TAIL(base))); + POSTING_READ_FW(RING_HEAD(base)); /* paranoia */ I915_WRITE_FW(RING_HEAD(base), 0); I915_WRITE_FW(RING_TAIL(base), 0); + POSTING_READ_FW(RING_TAIL(base)); /* The ring must be empty before it is disabled */ I915_WRITE_FW(RING_CTL(base), 0); |