drm/i915: Stop accessing crtc->state from the flip done irq

Assuming crtc->state is pointing at the correct thing for the
async flip commit is nonsense. If we had already queued up multiple
commits this would point at the very lates crtc state even if the
older commits hadn't even happened yet.

Instead properly stage/arm the event like we do for async flips.
Since we don't need to arm multiple of these at the same time we
don't need a list like the normal vblank even processing uses.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230928152450.30109-1-ville.syrjala@linux.intel.comReviewed-by: Arun R Murthy <arun.r.murthy@intel.com>

drivers/gpu/drm/i915/display/intel_crtc.c

@@ -553,8 +553,15 @@ void intel_pipe_update_start(struct intel_atomic_state *state,
 
 	intel_psr_lock(new_crtc_state);
 
-	if (new_crtc_state->do_async_flip)
+	if (new_crtc_state->do_async_flip) {
+		spin_lock_irq(&crtc->base.dev->event_lock);
+		/* arm the event for the flip done irq handler */
+		crtc->flip_done_event = new_crtc_state->uapi.event;
+		spin_unlock_irq(&crtc->base.dev->event_lock);
+
+		new_crtc_state->uapi.event = NULL;
 		return;
+	}
 
 	if (intel_crtc_needs_vblank_work(new_crtc_state))
 		intel_crtc_vblank_work_init(new_crtc_state);

drivers/gpu/drm/i915/display/intel_display_irq.c

@@ -340,16 +340,15 @@ static void flip_done_handler(struct drm_i915_private *i915,
 			      enum pipe pipe)
 {
 	struct intel_crtc *crtc = intel_crtc_for_pipe(i915, pipe);
-	struct drm_crtc_state *crtc_state = crtc->base.state;
-	struct drm_pending_vblank_event *e = crtc_state->event;
 	struct drm_device *dev = &i915->drm;
 	unsigned long irqflags;
 
 	spin_lock_irqsave(&dev->event_lock, irqflags);
 
-	crtc_state->event = NULL;
-
-	drm_crtc_send_vblank_event(&crtc->base, e);
+	if (crtc->flip_done_event) {
+		drm_crtc_send_vblank_event(&crtc->base, crtc->flip_done_event);
+		crtc->flip_done_event = NULL;
+	}
 
 	spin_unlock_irqrestore(&dev->event_lock, irqflags);
 }

drivers/gpu/drm/i915/display/intel_display_types.h

@@ -1475,6 +1475,9 @@ struct intel_crtc {
 
 	struct intel_crtc_state *config;
 
+	/* armed event for async flip */
+	struct drm_pending_vblank_event *flip_done_event;
+
 	/* Access to these should be protected by dev_priv->irq_lock. */
 	bool cpu_fifo_underrun_disabled;
 	bool pch_fifo_underrun_disabled;