[SRU][Q][PATCH 1/5] drm/i915/psr: Panel Replay SU cap dpcd read return value

[Aaron Ma]

From: Jouni Högander <jouni.hogander at intel.com>

BugLink: https://bugs.launchpad.net/bugs/2144637

Currently return value of drm_dpcd_readb is not checked when reading sink
Panel Replay Selective Update capabilities.

Fix this and switch to drm_dpcd_read_byte.

Signed-off-by: Jouni Högander <jouni.hogander at intel.com>
Reviewed-by: Mika Kahola <mika.kahola at intel.com>
Reviewed-by: Michał Grzelak <michal.grzelak at intel.com>
Link: https://lore.kernel.org/r/20250827060809.2461725-1-jouni.hogander@intel.com
(cherry picked from commit 90d8aad11f613e13e1eddc35c0225cce9e54ba94)
Signed-off-by: Aaron Ma <aaron.ma at canonical.com>
---
 drivers/gpu/drm/i915/display/intel_psr.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index debb0e8f321d8..e54b5c629b124 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -516,12 +516,14 @@ static u8 intel_dp_get_su_capability(struct intel_dp *intel_dp)
 {
 	u8 su_capability = 0;
 
-	if (intel_dp->psr.sink_panel_replay_su_support)
-		drm_dp_dpcd_readb(&intel_dp->aux,
-				  DP_PANEL_REPLAY_CAP_CAPABILITY,
-				  &su_capability);
-	else
+	if (intel_dp->psr.sink_panel_replay_su_support) {
+		if (drm_dp_dpcd_read_byte(&intel_dp->aux,
+					  DP_PANEL_REPLAY_CAP_CAPABILITY,
+					  &su_capability) < 0)
+			return 0;
+	} else {
 		su_capability = intel_dp->psr_dpcd[1];
+	}
 
 	return su_capability;
 }
-- 
2.43.0