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authorMika Kuoppala <mika.kuoppala@linux.intel.com>2012-12-10 15:41:48 +0200
committerDaniel Vetter <daniel.vetter@ffwll.ch>2012-12-11 13:32:26 +0100
commitf72b3435c1a75406d82d6e252bb78f009efd4bd9 (patch)
tree5b9e854dc74ca4d52374cd6e7e816312c6daca31
parent3ac18232946aacf0a9807c3143f8449ed4aa68f4 (diff)
drm/i915: Don't emit semaphore wait if wrap happened
If wrap just happened we need to prevent emitting waits for pre wrap values. Detect this and emit no-ops instead. v2: Use olr > seqno to detect wrap instead of *seqno == 0 as suggested by Chris Wilson. v3: Use last used seqno to detect the wraparound. From Chris Wilson v4: Fixed unnecessary last_seqno assigment References: https://bugs.freedesktop.org/show_bug.cgi?id=57967 Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
-rw-r--r--drivers/gpu/drm/i915/i915_drv.h2
-rw-r--r--drivers/gpu/drm/i915/i915_gem.c2
-rw-r--r--drivers/gpu/drm/i915/intel_ringbuffer.c26
3 files changed, 23 insertions, 7 deletions
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 2ab476df1dc..9da67824dde 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -671,7 +671,7 @@ typedef struct drm_i915_private {
struct pci_dev *bridge_dev;
struct intel_ring_buffer ring[I915_NUM_RINGS];
- uint32_t next_seqno;
+ uint32_t last_seqno, next_seqno;
drm_dma_handle_t *status_page_dmah;
struct resource mch_res;
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index e4b233df576..a81b78a59bd 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1969,7 +1969,7 @@ i915_gem_get_seqno(struct drm_device *dev, u32 *seqno)
dev_priv->next_seqno = 1;
}
- *seqno = dev_priv->next_seqno++;
+ *seqno = dev_priv->last_seqno = dev_priv->next_seqno++;
return 0;
}
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 0d03dc649c5..69bbe7bb9f6 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -596,6 +596,13 @@ gen6_add_request(struct intel_ring_buffer *ring)
return 0;
}
+static inline bool i915_gem_has_seqno_wrapped(struct drm_device *dev,
+ u32 seqno)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ return dev_priv->last_seqno < seqno;
+}
+
/**
* intel_ring_sync - sync the waiter to the signaller on seqno
*
@@ -626,11 +633,20 @@ gen6_ring_sync(struct intel_ring_buffer *waiter,
if (ret)
return ret;
- intel_ring_emit(waiter,
- dw1 | signaller->semaphore_register[waiter->id]);
- intel_ring_emit(waiter, seqno);
- intel_ring_emit(waiter, 0);
- intel_ring_emit(waiter, MI_NOOP);
+ /* If seqno wrap happened, omit the wait with no-ops */
+ if (likely(!i915_gem_has_seqno_wrapped(waiter->dev, seqno))) {
+ intel_ring_emit(waiter,
+ dw1 |
+ signaller->semaphore_register[waiter->id]);
+ intel_ring_emit(waiter, seqno);
+ intel_ring_emit(waiter, 0);
+ intel_ring_emit(waiter, MI_NOOP);
+ } else {
+ intel_ring_emit(waiter, MI_NOOP);
+ intel_ring_emit(waiter, MI_NOOP);
+ intel_ring_emit(waiter, MI_NOOP);
+ intel_ring_emit(waiter, MI_NOOP);
+ }
intel_ring_advance(waiter);
return 0;