drm/i915/guc: Take GT PM ref when deregistering context

Taking a PM reference to prevent intel_gt_wait_for_idle from short
circuiting while a deregister context H2G is in flight. To do this must
issue the deregister H2G from a worker as context can be destroyed from
an atomic context and taking GT PM ref blows up. Previously we took a
runtime PM from this atomic context which worked but will stop working
once runtime pm autosuspend in enabled.

So this patch is two fold, stop intel_gt_wait_for_idle from short
circuting and fix runtime pm autosuspend.

v2:
 (John Harrison)
  - Split structure changes out in different patch
 (Tvrtko)
  - Don't drop lock in deregister_destroyed_contexts
v3:
 (John Harrison)
  - Flush destroyed contexts before destroying context reg pool

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/20211014172005.27155-3-matthew.brost@intel.com

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
index e7e3984aab78..4613d027cbc3 100644
--- a/drivers/gpu/drm/i915/gt/intel_context_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
@@ -213,6 +213,13 @@ struct intel_context {
 		struct list_head link;
 	} guc_id;
 
+	/**
+	 * @destroyed_link: link in guc->submission_state.destroyed_contexts, in
+	 * list when context is pending to be destroyed (deregistered with the
+	 * GuC), protected by guc->submission_state.lock
+	 */
+	struct list_head destroyed_link;
+
 #ifdef CONFIG_DRM_I915_SELFTEST
 	/**
 	 * @drop_schedule_enable: Force drop of schedule enable G2H for selftest