2 files changed, 16 insertions, 7 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index ff6f870d6621..98322053eb2a 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -330,6 +330,7 @@ struct drm_i915_error_state {
         u64 fence[I915_MAX_NUM_FENCES];
         struct timeval time;
         struct drm_i915_error_ring {
+                bool valid;
                 struct drm_i915_error_object {
                         int page_count;
                         u32 gtt_offset;
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index a707cca692e4..d7fd2fd2f0a5 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -239,6 +239,9 @@ static void i915_ring_error_state(struct drm_i915_error_state_buf *m,
                                   unsigned ring)
 {
         BUG_ON(ring >= I915_NUM_RINGS); /* shut up confused gcc */
+        if (!error->ring[ring].valid)
+                return;
+
         err_printf(m, "%s command stream:\n", ring_str(ring));
         err_printf(m, "  HEAD: 0x%08x\n", error->head[ring]);
         err_printf(m, "  TAIL: 0x%08x\n", error->tail[ring]);
@@ -293,7 +296,6 @@ int i915_error_state_to_str(struct drm_i915_error_state_buf *m,
         struct drm_device *dev = error_priv->dev;
         drm_i915_private_t *dev_priv = dev->dev_private;
         struct drm_i915_error_state *error = error_priv->error;
-        struct intel_ring_buffer *ring;
         int i, j, page, offset, elt;
 
         if (!error) {
@@ -328,7 +330,7 @@ int i915_error_state_to_str(struct drm_i915_error_state_buf *m,
         if (INTEL_INFO(dev)->gen == 7)
                 err_printf(m, "ERR_INT: 0x%08x\n", error->err_int);
 
-        for_each_ring(ring, dev_priv, i)
+        for (i = 0; i < ARRAY_SIZE(error->ring); i++)
                 i915_ring_error_state(m, dev, error, i);
 
         if (error->active_bo)
@@ -385,8 +387,7 @@ int i915_error_state_to_str(struct drm_i915_error_state_buf *m,
                         }
                 }
 
-                obj = error->ring[i].ctx;
-                if (obj) {
+                if ((obj = error->ring[i].ctx)) {
                         err_printf(m, "%s --- HW Context = 0x%08x\n",
                                    dev_priv->ring[i].name,
                                    obj->gtt_offset);
@@ -667,7 +668,8 @@ i915_error_first_batchbuffer(struct drm_i915_private *dev_priv,
                         return NULL;
 
                 obj = ring->scratch.obj;
-                if (acthd >= i915_gem_obj_ggtt_offset(obj) &&
+                if (obj != NULL &&
+                    acthd >= i915_gem_obj_ggtt_offset(obj) &&
                     acthd < i915_gem_obj_ggtt_offset(obj) + obj->base.size)
                         return i915_error_object_create(dev_priv, obj);
         }
@@ -775,11 +777,17 @@ static void i915_gem_record_rings(struct drm_device *dev,
                                   struct drm_i915_error_state *error)
 {
         struct drm_i915_private *dev_priv = dev->dev_private;
-        struct intel_ring_buffer *ring;
         struct drm_i915_gem_request *request;
         int i, count;
 
-        for_each_ring(ring, dev_priv, i) {
+        for (i = 0; i < I915_NUM_RINGS; i++) {
+                struct intel_ring_buffer *ring = &dev_priv->ring[i];
+
+                if (ring->dev == NULL)
+                        continue;
+
+                error->ring[i].valid = true;
+
                 i915_record_ring_state(dev, error, ring);
 
                 error->ring[i].batchbuffer =