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path: root/drivers/gpu/drm/i915/intel_ringbuffer.c
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Diffstat (limited to 'drivers/gpu/drm/i915/intel_ringbuffer.c')
-rw-r--r--drivers/gpu/drm/i915/intel_ringbuffer.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index e5b84ff..b5e7bd9 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -280,8 +280,6 @@ static int init_ring_common(struct intel_ring_buffer *ring)
I915_WRITE_HEAD(ring, 0);
ring->write_tail(ring, 0);
- /* Initialize the ring. */
- I915_WRITE_START(ring, obj->gtt_offset);
head = I915_READ_HEAD(ring) & HEAD_ADDR;
/* G45 ring initialization fails to reset head to zero */
@@ -307,6 +305,11 @@ static int init_ring_common(struct intel_ring_buffer *ring)
}
}
+ /* Initialize the ring. This must happen _after_ we've cleared the ring
+ * registers with the above sequence (the readback of the HEAD registers
+ * also enforces ordering), otherwise the hw might lose the new ring
+ * register values. */
+ I915_WRITE_START(ring, obj->gtt_offset);
I915_WRITE_CTL(ring,
((ring->size - PAGE_SIZE) & RING_NR_PAGES)
| RING_VALID);