[PATCH v4 6/6] drm/i915/display: Wait for vblank in case of PSR is using trans push

[Jouni Högander]

In case PSR uses trans push as a "frame change" event and we need to wait
vblank after triggering PSR "frame change" event. Othervise we may miss
selective updates.

DSB skips all waits while PSR is active. Check push send is skipped as well
because trans push send bit is not clearn by the HW if VRR is not enabled
-> we may start configuring new selective update while previous is not
complete. Avoid this by waiting for vblank after sending trans push.

Signed-off-by: Jouni Högander <jouni.hogander at intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 456fc4b04cda..ebbead447eca 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -7294,9 +7294,27 @@ static void intel_atomic_dsb_finish(struct intel_atomic_state *state,
 				new_crtc_state->dsb_color);
 
 	if (new_crtc_state->use_dsb && !intel_color_uses_chained_dsb(new_crtc_state)) {
-		intel_dsb_wait_vblanks(new_crtc_state->dsb_commit, 1);
+		/*
+		 * Dsb wait vblank may or may not skip. Let's remove it for PSR
+		 * trans push case to ensure we are not waiting two vblanks
+		 */
+		if (!intel_psr_use_trans_push(new_crtc_state))
+			intel_dsb_wait_vblanks(new_crtc_state->dsb_commit, 1);
 
 		intel_vrr_send_push(new_crtc_state->dsb_commit, new_crtc_state);
+
+		/*
+		 * In case PSR uses trans push as a "frame change" event and
+		 * VRR is not in use we need to wait vblank. Othervise we may
+		 * miss selective updates. DSB skips all waits while PSR is
+		 * active. Check push send is skipped as well because trans push
+		 * send bit is not clearn by the HW if VRR is not enabled -> we
+		 * may start configuring new selective update while previous is
+		 * not complete.
+		 */
+		if (intel_psr_use_trans_push(new_crtc_state))
+			intel_dsb_wait_vblanks(new_crtc_state->dsb_commit, 1);
+
 		intel_dsb_wait_vblank_delay(state, new_crtc_state->dsb_commit);
 		intel_vrr_check_push_sent(new_crtc_state->dsb_commit,
 					  new_crtc_state);
-- 
2.43.0