[PATCH 5/6] drm/i915: Use safer intel_uncore_wait_for_register in ring-init

Chris Wilson chris at chris-wilson.co.uk
Tue Apr 11 10:28:46 UTC 2017


While we do hold the forcewake for legacy ringbuffer initialisation, we
don't guard our access with the uncore.lock spinlock. In theory, we only
initialise when no others should be accessing the same mmio cachelines,
but in practice be safe as this is an infrequently used path and not
worth risky micro-optimisations.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/intel_ringbuffer.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 331da59a1eb5..97d5fcca8805 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -538,9 +538,9 @@ static int init_ring_common(struct intel_engine_cs *engine)
 	I915_WRITE_CTL(engine, RING_CTL_SIZE(ring->size) | RING_VALID);
 
 	/* If the head is still not zero, the ring is dead */
-	if (intel_wait_for_register_fw(dev_priv, RING_CTL(engine->mmio_base),
-				       RING_VALID, RING_VALID,
-				       50)) {
+	if (intel_wait_for_register(dev_priv, RING_CTL(engine->mmio_base),
+				    RING_VALID, RING_VALID,
+				    50)) {
 		DRM_ERROR("%s initialization failed "
 			  "ctl %08x (valid? %d) head %08x [%08x] tail %08x [%08x] start %08x [expected %08x]\n",
 			  engine->name,
-- 
2.11.0



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