[Intel-gfx] [PATCH v2] drm/i915/psr: Add continuous full frame bit together with single

[Jouni Högander]

Currently we are observing occasionally display flickering or complete
freeze. This is narrowed down to be caused by single full frame update
(SFF).

SFF bit after it's written gets cleared by HW in subsequent vblank
i.e. when the update is sent to the panel. SFF bit is required to be
written together with partial frame update (PFU) bit. After the SFF
bit gets cleared by the HW psr2 man trk ctl register still contains
PFU bit. If there is subsequent update for any reason we will end up
having selective update/fetch configuration where start line is 0 and
end line is 0. Also selective fetch configuration for the planes is
not properly performed. This seems to be causing problems with some
panels.

Using CFF without SFF doesn't work either because it may happen that
psr2 man track ctl register is overwritten by next update before
vblank triggers sending the update. This is causing problems to
psr_invalidate/flush. Using CFF and SFF together solves the problems
as SFF is cleared only by HW in subsequent vblank and the update gets
sent.

Fix the flickering/freeze issue by keeping CFF bit as set when PSR2 is
enabled unless there is a properly configured selective update via
atomic commit.

v2:
 - Improve commit message and comments
 - No functional changes

This is also workaround for HSD 14014971508

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: José Roberto de Souza <jose.souza at intel.com>
Cc: Mika Kahola <mika.kahola at intel.com>

Reported-by: Lee Shawn C <shawn.c.lee at intel.com>
Signed-off-by: Jouni Högander <jouni.hogander at intel.com>
Tested-by: Lee Shawn C <shawn.c.lee at intel.com>
---
 drivers/gpu/drm/i915/display/intel_psr.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index 5b678916e6db..619d532bf322 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -1510,7 +1510,8 @@ static void psr_force_hw_tracking_exit(struct intel_dp *intel_dp)
 			       PSR2_MAN_TRK_CTL(intel_dp->psr.transcoder),
 			       man_trk_ctl_enable_bit_get(dev_priv) |
 			       man_trk_ctl_partial_frame_bit_get(dev_priv) |
-			       man_trk_ctl_single_full_frame_bit_get(dev_priv));
+			       man_trk_ctl_single_full_frame_bit_get(dev_priv) |
+			       man_trk_ctl_continuos_full_frame(dev_priv));
 
 	/*
 	 * Display WA #0884: skl+
@@ -1624,11 +1625,8 @@ static void psr2_man_trk_ctl_calc(struct intel_crtc_state *crtc_state,
 	val |= man_trk_ctl_partial_frame_bit_get(dev_priv);
 
 	if (full_update) {
-		/*
-		 * Not applying Wa_14014971508:adlp as we do not support the
-		 * feature that requires this workaround.
-		 */
 		val |= man_trk_ctl_single_full_frame_bit_get(dev_priv);
+		val |= man_trk_ctl_continuos_full_frame(dev_priv);
 		goto exit;
 	}
 
@@ -2307,12 +2305,15 @@ static void _psr_flush_handle(struct intel_dp *intel_dp)
 			/* can we turn CFF off? */
 			if (intel_dp->psr.busy_frontbuffer_bits == 0) {
 				u32 val = man_trk_ctl_enable_bit_get(dev_priv) |
-					  man_trk_ctl_partial_frame_bit_get(dev_priv) |
-					  man_trk_ctl_single_full_frame_bit_get(dev_priv);
+					man_trk_ctl_partial_frame_bit_get(dev_priv) |
+					man_trk_ctl_single_full_frame_bit_get(dev_priv) |
+					man_trk_ctl_continuos_full_frame(dev_priv);
 
 				/*
-				 * turn continuous full frame off and do a single
-				 * full frame
+				 * Set psr2_sel_fetch_cff_enabled as false to allow selective
+				 * updates. Still keep cff bit enabled as we don't have proper
+				 * SU configuration in case update is sent for any reason after
+				 * sff bit gets cleared by the HW on next vblank.
 				 */
 				intel_de_write(dev_priv, PSR2_MAN_TRK_CTL(intel_dp->psr.transcoder),
 					       val);
-- 
2.34.1