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Commit 629e8941 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/ringbuffer: Ignore failure to setup the ring on Sandybridge 

The ring buffer registers return 0 whilst idle (for some values of idle)
on early Sandybridge hw. Persevere even when all appears hopeless...
Fortunately the head auto-reporting prevents most hangs.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=31370


Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
parent ae69b42a

drivers/gpu/drm/i915/intel_ringbuffer.c

+24 −8
Original line number Original line Diff line number Diff line
@@ -180,6 +180,21 @@ static int init_ring_common(struct intel_ring_buffer *ring) 
	if ((I915_READ_CTL(ring) & RING_VALID) == 0 ||

	if ((I915_READ_CTL(ring) & RING_VALID) == 0 ||

	    I915_READ_START(ring) != obj_priv->gtt_offset ||

	    I915_READ_START(ring) != obj_priv->gtt_offset ||

	    (I915_READ_HEAD(ring) & HEAD_ADDR) != 0) {

	    (I915_READ_HEAD(ring) & HEAD_ADDR) != 0) {

		if (IS_GEN6(ring->dev) && ring->dev->pdev->revision <= 8) {

			/* Early revisions of Sandybridge do not like

			 * revealing the contents of the ring buffer

			 * registers whilst idle. Fortunately, the

			 * auto-reporting mechanism prevents most hangs,

			 * but this will bite us eventually...

			 */

			DRM_DEBUG("%s initialization failed "

				  "ctl %08x head %08x tail %08x start %08x. Ignoring, hope for the best!\n",

				  ring->name,

				  I915_READ_CTL(ring),

				  I915_READ_HEAD(ring),

				  I915_READ_TAIL(ring),

				  I915_READ_START(ring));

		} else {

			DRM_ERROR("%s initialization failed "

			DRM_ERROR("%s initialization failed "

				  "ctl %08x head %08x tail %08x start %08x\n",

				  "ctl %08x head %08x tail %08x start %08x\n",

				  ring->name,

				  ring->name,
@@ -189,6 +204,7 @@ static int init_ring_common(struct intel_ring_buffer *ring) 
				  I915_READ_START(ring));

				  I915_READ_START(ring));

			return -EIO;

			return -EIO;

		}

		}

	}





	if (!drm_core_check_feature(ring->dev, DRIVER_MODESET))

	if (!drm_core_check_feature(ring->dev, DRIVER_MODESET))

		i915_kernel_lost_context(ring->dev);

		i915_kernel_lost_context(ring->dev);