drm/i915: Wait for engines to idle before retiring

In the next^W forthcoming patch, we will start to defer retiring the
request from the engine list if it is still active on the submission
backend. To preserve the semantics that after wait-for-idle completes
the system is idle and fully retired, we need to therefore wait for the
backends to idle before calling i915_retire_requests().

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180627115334.16282-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 858d188..5a9cae6 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3810,10 +3810,13 @@ int i915_gem_wait_for_idle(struct drm_i915_private *i915, unsigned int flags)
                        if (err)
                                return err;
                }
+
+               err = wait_for_engines(i915);
+               if (err)
+                       return err;
+
                i915_retire_requests(i915);
                GEM_BUG_ON(i915->gt.active_requests);
-
-               return wait_for_engines(i915);
        } else {
                struct intel_engine_cs *engine;
                enum intel_engine_id id;
@@ -3824,9 +3827,9 @@ int i915_gem_wait_for_idle(struct drm_i915_private *i915, unsigned int flags)
                        if (err)
                                return err;
                }
-
-               return 0;
        }
+
+       return 0;
 }
 
 static void __i915_gem_object_flush_for_display(struct drm_i915_gem_object *obj)