drm/msm: dpu: Don't queue the frame_done watchdog for cursor

In the case of an async/cursor update, we don't wait for the frame_done
event, which means handle_frame_done is never called, and the frame_done
watchdog isn't canceled. Currently, this results in a frame_done timeout
every time the cursor moves without a synchronous frame following it up
before the timeout expires. Since we don't wait for frame_done, and
don't handle it, we shouldn't modify the watchdog.
Reviewed-by: Fritz Koenig <frkoenig@google.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190128204306.95076-4-sean@poorly.runSigned-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c

@@ -1791,7 +1791,6 @@ void dpu_encoder_kickoff(struct drm_encoder *drm_enc, bool async)
 {
 	struct dpu_encoder_virt *dpu_enc;
 	struct dpu_encoder_phys *phys;
-	unsigned long timeout_ms;
 	ktime_t wakeup_time;
 	unsigned int i;
 
@@ -1804,12 +1803,20 @@ void dpu_encoder_kickoff(struct drm_encoder *drm_enc, bool async)
 
 	trace_dpu_enc_kickoff(DRMID(drm_enc));
 
+	/*
+	 * Asynchronous frames don't handle FRAME_DONE events. As such, they
+	 * shouldn't enable the frame_done watchdog since it will always time
+	 * out.
+	 */
+	if (!async) {
+		unsigned long timeout_ms;
 		timeout_ms = DPU_ENCODER_FRAME_DONE_TIMEOUT_FRAMES * 1000 /
 			drm_mode_vrefresh(&drm_enc->crtc->state->adjusted_mode);
 
 		atomic_set(&dpu_enc->frame_done_timeout_ms, timeout_ms);
 		mod_timer(&dpu_enc->frame_done_timer,
 			  jiffies + msecs_to_jiffies(timeout_ms));
+	}
 
 	/* All phys encs are ready to go, trigger the kickoff */
 	_dpu_encoder_kickoff_phys(dpu_enc, async);