[PATCH xf86-video-amdgpu] Fix hang when entering into dpms-off mode

[Aaron Liu]

The hang happened in CTS 4.6 glcts. It is dued to inconsistent process
in amdgpu_dri2_schedule_swap when system entering into dpms-off mode.

Normally, drmmode_wait_vblank will be excuted. But when entering into
dpms-off mode, drmmode_wait_vblank can't be excuted and fallback to
amdgpu_dri2_schedule_event to process.
Finally in amdgpu_dri2_deferred_event, vblank_handler will be excuted.
It is the root cause of hang. Instead of vblank_handler, it just use
amdgpu_dri2_frame_event_handler to process under dpms-off mode.

Change-Id: I6bfed9692fc02c8c3c86df2a816884c4a1f46cb1
Signed-off-by: Aaron Liu <aaron.liu at amd.com>
---
 src/amdgpu_dri2.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/amdgpu_dri2.c b/src/amdgpu_dri2.c
index a6b76a1..c54ad0c 100644
--- a/src/amdgpu_dri2.c
+++ b/src/amdgpu_dri2.c
@@ -884,7 +884,7 @@ CARD32 amdgpu_dri2_deferred_event(OsTimerPtr timer, CARD32 now, pointer data)
 	if (ret) {
 		xf86DrvMsg(scrn->scrnIndex, X_ERROR,
 			   "%s cannot get current time\n", __func__);
-		if (event_info->drm_queue_seq)
+		if (event_info->drm_queue_seq && amdgpu_crtc_is_enabled(crtc))
 			drmmode_crtc->drmmode->event_context.
 				vblank_handler(pAMDGPUEnt->fd, 0, 0, 0,
 					       (void*)event_info->drm_queue_seq);
@@ -900,7 +900,12 @@ CARD32 amdgpu_dri2_deferred_event(OsTimerPtr timer, CARD32 now, pointer data)
 	delta_seq = delta_t * drmmode_crtc->dpms_last_fps;
 	delta_seq /= 1000000;
 	frame = (CARD64) drmmode_crtc->dpms_last_seq + delta_seq;
-	if (event_info->drm_queue_seq)
+	/*
+	 * If CRTC is in DPMS off state, it can't use vblank_handler.
+	 * Because drmmode_wait_vblank is not excuted in such as
+	 * amdgpu_dri2_schedule_swap/amdgpu_dri2_schedule_wait_msc.
+	 */
+	if (event_info->drm_queue_seq && amdgpu_crtc_is_enabled(crtc))
 		drmmode_crtc->drmmode->event_context.
 			vblank_handler(pAMDGPUEnt->fd, frame, drm_now / 1000000,
 				       drm_now % 1000000,
-- 
2.7.4