[Intel-gfx] [PATCH] drm/i915: Include HW status page in error capture

[Chris Wilson]

Many times in the past we have concluded that the cause of the GPU hang
has been that the hw status page was stale, usually because the GPU and
CPU disagreed over the address of the page. Having stumbled across yet
another issue that seems to be related to the HWSP, it is time to
include that information in the GPU error dump.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_drv.h       |  3 ++-
 drivers/gpu/drm/i915/i915_gpu_error.c | 50 +++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 64a1aca7804d..b6887a88424d 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -309,6 +309,7 @@ struct drm_i915_error_state {
 	u32 tail[I915_NUM_RINGS];
 	u32 head[I915_NUM_RINGS];
 	u32 ctl[I915_NUM_RINGS];
+	u32 hws[I915_NUM_RINGS];
 	u32 ipeir[I915_NUM_RINGS];
 	u32 ipehr[I915_NUM_RINGS];
 	u32 instdone[I915_NUM_RINGS];
@@ -339,7 +340,7 @@ struct drm_i915_error_state {
 			int page_count;
 			u32 gtt_offset;
 			u32 *pages[0];
-		} *ringbuffer, *batchbuffer, *ctx;
+		} *ringbuffer, *batchbuffer, *ctx, *hws;
 		struct drm_i915_error_request {
 			long jiffies;
 			u32 seqno;
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index e2af1d490f8d..a6b100b1dff5 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -247,6 +247,7 @@ static void i915_ring_error_state(struct drm_i915_error_state_buf *m,
 	err_printf(m, "  HEAD: 0x%08x\n", error->head[ring]);
 	err_printf(m, "  TAIL: 0x%08x\n", error->tail[ring]);
 	err_printf(m, "  CTL: 0x%08x\n", error->ctl[ring]);
+	err_printf(m, "  HWS: 0x%08x\n", error->hws[ring]);
 	err_printf(m, "  ACTHD: 0x%08x\n", error->acthd[ring]);
 	err_printf(m, "  IPEIR: 0x%08x\n", error->ipeir[ring]);
 	err_printf(m, "  IPEHR: 0x%08x\n", error->ipehr[ring]);
@@ -390,6 +391,22 @@ int i915_error_state_to_str(struct drm_i915_error_state_buf *m,
 			}
 		}
 
+		if ((obj = error->ring[i].hws)) {
+			err_printf(m, "%s --- HW Status = 0x%08x\n",
+				   dev_priv->ring[i].name,
+				   obj->gtt_offset);
+			offset = 0;
+			for (elt = 0; elt < PAGE_SIZE/16; elt += 4) {
+				err_printf(m, "[%04x] %08x %08x %08x %08x\n",
+					   offset,
+					   obj->pages[0][elt],
+					   obj->pages[0][elt+1],
+					   obj->pages[0][elt+2],
+					   obj->pages[0][elt+3]);
+					offset += 16;
+			}
+		}
+
 		if ((obj = error->ring[i].ctx)) {
 			err_printf(m, "%s --- HW Context = 0x%08x\n",
 				   dev_priv->ring[i].name,
@@ -472,6 +489,7 @@ static void i915_error_state_free(struct kref *error_ref)
 	for (i = 0; i < ARRAY_SIZE(error->ring); i++) {
 		i915_error_object_free(error->ring[i].batchbuffer);
 		i915_error_object_free(error->ring[i].ringbuffer);
+		i915_error_object_free(error->ring[i].hws);
 		i915_error_object_free(error->ring[i].ctx);
 		kfree(error->ring[i].requests);
 	}
@@ -793,6 +811,35 @@ static void i915_record_ring_state(struct drm_device *dev,
 	error->tail[ring->id] = I915_READ_TAIL(ring);
 	error->ctl[ring->id] = I915_READ_CTL(ring);
 
+	if (I915_NEED_GFX_HWS(dev)) {
+		int mmio;
+
+		if (IS_GEN7(dev)) {
+			switch (ring->id) {
+			default:
+			case RCS:
+				mmio = RENDER_HWS_PGA_GEN7;
+				break;
+			case BCS:
+				mmio = BLT_HWS_PGA_GEN7;
+				break;
+			case VCS:
+				mmio = BSD_HWS_PGA_GEN7;
+				break;
+			case VECS:
+				mmio = VEBOX_HWS_PGA_GEN7;
+				break;
+			}
+		} else if (IS_GEN6(ring->dev)) {
+			mmio = RING_HWS_PGA_GEN6(ring->mmio_base);
+		} else {
+			/* XXX: gen8 returns to sanity */
+			mmio = RING_HWS_PGA(ring->mmio_base);
+		}
+
+		error->hws[ring->id] = I915_READ(mmio);
+	}
+
 	error->cpu_ring_head[ring->id] = ring->head;
 	error->cpu_ring_tail[ring->id] = ring->tail;
 
@@ -846,6 +893,9 @@ static void i915_gem_record_rings(struct drm_device *dev,
 		error->ring[i].ringbuffer =
 			i915_error_ggtt_object_create(dev_priv, ring->obj);
 
+		if (ring->status_page.obj)
+			error->ring[i].hws =
+				i915_error_ggtt_object_create(dev_priv, ring->status_page.obj);
 
 		i915_gem_record_active_context(ring, error, &error->ring[i]);
 
-- 
1.8.5.3