drm/i915/guc: Insert fence on context when deregistering

Sometimes during context pinning a context with the same guc_id is
registered with the GuC. In this a case deregister must be done before
the context can be registered. A fence is inserted on all requests while
the deregister is in flight. Once the G2H is received indicating the
deregistration is complete the context is registered and the fence is
released.

v2:
 (John H)
  - Fix commit message

Cc: John Harrison <john.c.harrison@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <john.c.harrison@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210721215101.139794-8-matthew.brost@intel.com

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index 5deb65ec5fa5..717e5b292046 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -285,6 +285,14 @@ struct i915_request {
 		struct hrtimer timer;
 	} watchdog;
 
+	/*
+	 * Requests may need to be stalled when using GuC submission waiting for
+	 * certain GuC operations to complete. If that is the case, stalled
+	 * requests are added to a per context list of stalled requests. The
+	 * below list_head is the link in that list.
+	 */
+	struct list_head guc_fence_link;
+
 	I915_SELFTEST_DECLARE(struct {
 		struct list_head link;
 		unsigned long delay;