disp: msm: sde: cache encoder_mask for vblank_work

There is a race between disable commit swap-state on display
thread and vblank work on event thread which may skip applying
the vblank vote if the encoder_mask has already been cleared.
To avoid the race, use a cached encoder_mask that is gauranteed
to be valid between the vblank_on and vblank_off calls.

Also, vblank queue work is initializing a variable that's never
used and msm_disable_outputs has 2 instances of pointers to old
CRTC state. Remove this dead code.

Change-Id: I5e4a482b8f067e272a2aef5afa08cc0e1ab89434
Signed-off-by: Steve Cohen <cohens@codeaurora.org>

msm/sde/sde_crtc.c

@@ -3820,13 +3820,13 @@ void sde_crtc_commit_kickoff(struct drm_crtc *crtc,
 }
 
 /**
- * _sde_crtc_vblank_enable_no_lock - update power resource and vblank request
+ * _sde_crtc_vblank_enable - update power resource and vblank request
  * @sde_crtc: Pointer to sde crtc structure
  * @enable: Whether to enable/disable vblanks
  *
  * @Return: error code
  */
-static int _sde_crtc_vblank_enable_no_lock(
+static int _sde_crtc_vblank_enable(
 		struct sde_crtc *sde_crtc, bool enable)
 {
 	struct drm_crtc *crtc;
@@ -3838,38 +3838,38 @@ static int _sde_crtc_vblank_enable_no_lock(
 	}
 
 	crtc = &sde_crtc->base;
+	SDE_EVT32(DRMID(crtc), enable, sde_crtc->enabled,
+			crtc->state->encoder_mask,
+			sde_crtc->cached_encoder_mask);
 
 	if (enable) {
 		int ret;
 
-		/* drop lock since power crtc cb may try to re-acquire lock */
-		mutex_unlock(&sde_crtc->crtc_lock);
 		ret = pm_runtime_get_sync(crtc->dev->dev);
-		mutex_lock(&sde_crtc->crtc_lock);
 		if (ret < 0)
 			return ret;
 
+		mutex_lock(&sde_crtc->crtc_lock);
 		drm_for_each_encoder_mask(enc, crtc->dev,
-				crtc->state->encoder_mask) {
-			SDE_EVT32(DRMID(&sde_crtc->base), DRMID(enc), enable,
-					sde_crtc->enabled);
+				sde_crtc->cached_encoder_mask) {
+			SDE_EVT32(DRMID(crtc), DRMID(enc));
 
 			sde_encoder_register_vblank_callback(enc,
 					sde_crtc_vblank_cb, (void *)crtc);
 		}
+
+		mutex_unlock(&sde_crtc->crtc_lock);
 	} else {
+		mutex_lock(&sde_crtc->crtc_lock);
 		drm_for_each_encoder_mask(enc, crtc->dev,
-				crtc->state->encoder_mask) {
-			SDE_EVT32(DRMID(&sde_crtc->base), DRMID(enc), enable,
-					sde_crtc->enabled);
+				sde_crtc->cached_encoder_mask) {
+			SDE_EVT32(DRMID(crtc), DRMID(enc));
 
 			sde_encoder_register_vblank_callback(enc, NULL, NULL);
 		}
 
-		/* drop lock since power crtc cb may try to re-acquire lock */
 		mutex_unlock(&sde_crtc->crtc_lock);
 		pm_runtime_put_sync(crtc->dev->dev);
-		mutex_lock(&sde_crtc->crtc_lock);
 	}
 
 	return 0;
@@ -4165,9 +4165,10 @@ static void sde_crtc_disable(struct drm_crtc *crtc)
 	kthread_cancel_delayed_work_sync(&sde_crtc->static_cache_read_work);
 	kthread_cancel_delayed_work_sync(&sde_crtc->idle_notify_work);
 
-	SDE_EVT32(DRMID(crtc), sde_crtc->enabled,
-			crtc->state->active, crtc->state->enable);
+	SDE_EVT32(DRMID(crtc), sde_crtc->enabled, crtc->state->active,
+			crtc->state->enable, sde_crtc->cached_encoder_mask);
 	sde_crtc->enabled = false;
+	sde_crtc->cached_encoder_mask = 0;
 
 	/* Try to disable uidle */
 	sde_core_perf_crtc_update_uidle(crtc, false);
@@ -4276,8 +4277,11 @@ static void sde_crtc_enable(struct drm_crtc *crtc,
 	 * Avoid drm_crtc_vblank_on during seamless DMS case
 	 * when CRTC is already in enabled state
 	 */
-	if (!sde_crtc->enabled)
+	if (!sde_crtc->enabled) {
+		/* cache the encoder mask now for vblank work */
+		sde_crtc->cached_encoder_mask = crtc->state->encoder_mask;
 		drm_crtc_vblank_on(crtc);
+	}
 
 	mutex_lock(&sde_crtc->crtc_lock);
 	SDE_EVT32(DRMID(crtc), sde_crtc->enabled);
@@ -5116,15 +5120,11 @@ int sde_crtc_vblank(struct drm_crtc *crtc, bool en)
 	}
 	sde_crtc = to_sde_crtc(crtc);
 
-	mutex_lock(&sde_crtc->crtc_lock);
-	SDE_EVT32(DRMID(&sde_crtc->base), en, sde_crtc->enabled);
-	ret = _sde_crtc_vblank_enable_no_lock(sde_crtc, en);
+	ret = _sde_crtc_vblank_enable(sde_crtc, en);
 	if (ret)
 		SDE_ERROR("%s vblank enable failed: %d\n",
 				sde_crtc->name, ret);
 
-	mutex_unlock(&sde_crtc->crtc_lock);
-
 	return 0;
 }