diff options
authorChris Wilson <chris@chris-wilson.co.uk>2014-01-02 14:32:35 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-02-13 13:48:03 -0800
commit98e0694d0e679e7018b6617f48fa04b7b888cef3 (patch)
parentc3c43400a29dba30a581c97a6eb6952d187c3e07 (diff)
drm/i915: Flush outstanding requests before allocating new seqno
commit 304d695c3dc8eb65206b9eaf16f8d1a41510d1cf upstream. In very rare cases (such as a memory failure stress test) it is possible to fill the entire ring without emitting a request. Under this circumstance, the outstanding request is flushed and waited upon. After space on the ring is cleared, we return to emitting the new command - except that we just cleared the seqno allocated for this operation and trigger the sanity check that a request is only ever emitted with a valid seqno. The fix is to rearrange the code to make sure the allocation of the seqno for this operation is after any required flushes of outstanding operations. The bug exists since the preallocation was introduced in commit 9d7730914f4cd496e356acfab95b41075aa8eae8 Author: Chris Wilson <chris@chris-wilson.co.uk> Date: Tue Nov 27 16:22:52 2012 +0000 drm/i915: Preallocate next seqno before touching the ring Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 8 insertions, 4 deletions
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 48fe23e8d18..629527d205d 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1459,8 +1459,8 @@ intel_ring_alloc_seqno(struct intel_ring_buffer *ring)
return i915_gem_get_seqno(ring->dev, &ring->outstanding_lazy_request);
-static int __intel_ring_begin(struct intel_ring_buffer *ring,
- int bytes)
+static int __intel_ring_prepare(struct intel_ring_buffer *ring,
+ int bytes)
int ret;
@@ -1476,7 +1476,6 @@ static int __intel_ring_begin(struct intel_ring_buffer *ring,
return ret;
- ring->space -= bytes;
return 0;
@@ -1491,12 +1490,17 @@ int intel_ring_begin(struct intel_ring_buffer *ring,
if (ret)
return ret;
+ ret = __intel_ring_prepare(ring, num_dwords * sizeof(uint32_t));
+ if (ret)
+ return ret;
/* Preallocate the olr before touching the ring */
ret = intel_ring_alloc_seqno(ring);
if (ret)
return ret;
- return __intel_ring_begin(ring, num_dwords * sizeof(uint32_t));
+ ring->space -= num_dwords * sizeof(uint32_t);
+ return 0;
void intel_ring_init_seqno(struct intel_ring_buffer *ring, u32 seqno)