drm/i915: make semaphore signaller detection more robust (921d42ea) · Commits · 戴 / test

Extract all this logic into a new helper function semaphore_wait_to_signaller_ring because: - The current code has way too much magic. - The current code doesn't look at bi16, which encodes VECS signallers on HSW. Those are just added after the fact, so can't be encoded in a neat formula. - The current logic can't blow up since it limits its value range sufficiently, but that's a bit too tricky to rely on in my opinion. Especially when we start to add bdw support. - I'm not a big fan of the explicit ring->semaphore_register list, but I think it's more robust to use the same mapping both when constructing the semaphore commands and when decoding them. - Finally add a FIXME comment about lack of broadwell support here, like in the earlier ipehr semaphore cmd detection function. Cc: Mika Kuoppala <mika.kuoppala@intel.com> Cc: Ben Widawsky <ben@bwidawsk.net> Cc: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by:

Mika Kuoppala <mika.kuoppala@intel.com> [danvet: Actually drop the untrue claim in the commit message Chris pointed out.] Signed-off-by:

Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_irq.c

+34 −1

Original line number	Diff line number	Diff line
		@@ -2518,6 +2518,39 @@ ipehr_is_semaphore_wait(struct drm_device *dev, u32 ipehr)
		}
		}

		static struct intel_ring_buffer *
		semaphore_wait_to_signaller_ring(struct intel_ring_buffer *ring, u32 ipehr)
		{
		struct drm_i915_private *dev_priv = ring->dev->dev_private;
		struct intel_ring_buffer *signaller;
		int i;

		if (INTEL_INFO(dev_priv->dev)->gen >= 8) {
		/*
		* FIXME: gen8 semaphore support - currently we don't emit
		* semaphores on bdw anyway, but this needs to be addressed when
		* we merge that code.
		*/
		return NULL;
		} else {
		u32 sync_bits = ipehr & MI_SEMAPHORE_SYNC_MASK;

		for_each_ring(signaller, dev_priv, i) {
		if(ring == signaller)
		continue;

		if (sync_bits ==
		signaller->semaphore_register[ring->id])
		return signaller;
		}
		}

		DRM_ERROR("No signaller ring found for ring %i, ipehr 0x%08x\n",
		ring->id, ipehr);

		return NULL;
		}

		static struct intel_ring_buffer *
		semaphore_waits_for(struct intel_ring_buffer ring, u32 seqno)
		{
		@@ -2558,7 +2591,7 @@ semaphore_waits_for(struct intel_ring_buffer ring, u32 seqno)
		return NULL;

		*seqno = ioread32(ring->virtual_start + head + 4) + 1;
		return &dev_priv->ring[(ring->id + (((ipehr >> 17) & 1) + 1)) % 3];
		return semaphore_wait_to_signaller_ring(ring, ipehr);
		}

		static int semaphore_passed(struct intel_ring_buffer *ring)

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