summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorDaniel Vetter <daniel.vetter@ffwll.ch>2012-08-07 09:54:14 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-08-26 15:12:11 -0700
commit413b13d9dd468992591bafb55e849c87fb68341c (patch)
treefc574815824ed2efaf99c580d56316643041b9de
parent318095d39c962873a6aa0f31683745cb0420753e (diff)
drm/i915: correctly order the ring init sequence
commit 0d8957c8a90bbb5d34fab9a304459448a5131e06 upstream. We may only start to set up the new register values after having confirmed that the ring is truely off. Otherwise the hw might lose the newly written register values. This is caught later on in the init sequence, when we check whether the register writes have stuck. Reviewed-by: Jani Nikula <jani.nikula@intel.com> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=50522 Tested-by: Yang Guang <guang.a.yang@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-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 2d6039b4571f..3bd85f7e3904 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -150,8 +150,6 @@ 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 */
@@ -177,6 +175,11 @@ 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_REPORT_64K | RING_VALID);