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Commit f72b3435 authored by Mika Kuoppala's avatar Mika Kuoppala Committed by Daniel Vetter
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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: default avatarMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 3ac18232

drivers/gpu/drm/i915/i915_drv.h

+1 −1
Original line number Original line Diff line number Diff line
@@ -671,7 +671,7 @@ typedef struct drm_i915_private { 




	struct pci_dev *bridge_dev;

	struct pci_dev *bridge_dev;

	struct intel_ring_buffer ring[I915_NUM_RINGS];

	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;

	drm_dma_handle_t *status_page_dmah;

	struct resource mch_res;

	struct resource mch_res;

drivers/gpu/drm/i915/i915_gem.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -1969,7 +1969,7 @@ i915_gem_get_seqno(struct drm_device *dev, u32 *seqno) 
		dev_priv->next_seqno = 1;

		dev_priv->next_seqno = 1;

	}

	}





	*seqno = dev_priv->next_seqno++;

	*seqno = dev_priv->last_seqno = dev_priv->next_seqno++;

	return 0;

	return 0;

}

}

drivers/gpu/drm/i915/intel_ringbuffer.c

+21 −5
Original line number Original line Diff line number Diff line
@@ -596,6 +596,13 @@ gen6_add_request(struct intel_ring_buffer *ring) 
	return 0;

	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

 * 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)

	if (ret)

		return ret;

		return ret;





	/* If seqno wrap happened, omit the wait with no-ops */

	if (likely(!i915_gem_has_seqno_wrapped(waiter->dev, seqno))) {

		intel_ring_emit(waiter,

		intel_ring_emit(waiter,

			dw1 | signaller->semaphore_register[waiter->id]);

				dw1 |

				signaller->semaphore_register[waiter->id]);

		intel_ring_emit(waiter, seqno);

		intel_ring_emit(waiter, seqno);

		intel_ring_emit(waiter, 0);

		intel_ring_emit(waiter, 0);

		intel_ring_emit(waiter, MI_NOOP);

		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);

	intel_ring_advance(waiter);





	return 0;

	return 0;