1 files changed, 14 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index f2a825e39646..8727086cf48c 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2114,6 +2114,9 @@ void i915_gem_track_fb(struct drm_i915_gem_object *old,
  * number comparisons on buffer last_read|write_seqno. It also allows an
  * emission time to be associated with the request for tracking how far ahead
  * of the GPU the submission is.
+ *
+ * The requests are reference counted, so upon creation they should have an
+ * initial reference taken using kref_init
  */
 struct drm_i915_gem_request {
         struct kref ref;
@@ -2137,7 +2140,16 @@ struct drm_i915_gem_request {
         /** Position in the ringbuffer of the end of the whole request */
         u32 tail;
 
-        /** Context related to this request */
+        /**
+         * Context related to this request
+         * Contexts are refcounted, so when this request is associated with a
+         * context, we must increment the context's refcount, to guarantee that
+         * it persists while any request is linked to it. Requests themselves
+         * are also refcounted, so the request will only be freed when the last
+         * reference to it is dismissed, and the code in
+         * i915_gem_request_free() will then decrement the refcount on the
+         * context.
+         */
         struct intel_context *ctx;
 
         /** Batch buffer related to this request if any */
@@ -2374,6 +2386,7 @@ struct drm_i915_cmd_table {
                                  (INTEL_DEVID(dev) & 0xFF00) == 0x0C00)
 #define IS_BDW_ULT(dev)         (IS_BROADWELL(dev) && \
                                  ((INTEL_DEVID(dev) & 0xf) == 0x6 ||    \
+                                 (INTEL_DEVID(dev) & 0xf) == 0xb ||     \
                                  (INTEL_DEVID(dev) & 0xf) == 0xe))
 #define IS_BDW_GT3(dev)         (IS_BROADWELL(dev) && \
                                  (INTEL_DEVID(dev) & 0x00F0) == 0x0020)