drm/i915/psr: Check drm_dp_dpcd_read return value on PSR dpcd init

Currently we are ignoriong drm_dp_dpcd_read return values when reading PSR
and Panel Replay capability DPCD register. Rework intel_psr_dpcd a bit to
take care of checking the return value.

v2: use drm_dp_dpcd_read_data

Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://lore.kernel.org/r/20250821045918.17757-1-jouni.hogander@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index 465f12c39330df21382c78553191eefce9faa072..eec4f7dc2d6683ef65de2a31febec5fce4875a41 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -580,6 +580,16 @@ exit:
 static void _panel_replay_init_dpcd(struct intel_dp *intel_dp)
 {
        struct intel_display *display = to_intel_display(intel_dp);
+       int ret;
+
+       ret = drm_dp_dpcd_read_data(&intel_dp->aux, DP_PANEL_REPLAY_CAP_SUPPORT,
+                                   &intel_dp->pr_dpcd, sizeof(intel_dp->pr_dpcd));
+       if (ret < 0)
+               return;
+
+       if (!(intel_dp->pr_dpcd[INTEL_PR_DPCD_INDEX(DP_PANEL_REPLAY_CAP_SUPPORT)] &
+             DP_PANEL_REPLAY_SUPPORT))
+               return;
 
        if (intel_dp_is_edp(intel_dp)) {
                if (!intel_alpm_aux_less_wake_supported(intel_dp)) {
@@ -611,6 +621,15 @@ static void _panel_replay_init_dpcd(struct intel_dp *intel_dp)
 static void _psr_init_dpcd(struct intel_dp *intel_dp)
 {
        struct intel_display *display = to_intel_display(intel_dp);
+       int ret;
+
+       ret = drm_dp_dpcd_read_data(&intel_dp->aux, DP_PSR_SUPPORT, intel_dp->psr_dpcd,
+                                   sizeof(intel_dp->psr_dpcd));
+       if (ret < 0)
+               return;
+
+       if (!intel_dp->psr_dpcd[0])
+               return;
 
        drm_dbg_kms(display->drm, "eDP panel supports PSR version %x\n",
                    intel_dp->psr_dpcd[0]);
@@ -656,18 +675,9 @@ static void _psr_init_dpcd(struct intel_dp *intel_dp)
 
 void intel_psr_init_dpcd(struct intel_dp *intel_dp)
 {
-       drm_dp_dpcd_read(&intel_dp->aux, DP_PSR_SUPPORT, intel_dp->psr_dpcd,
-                        sizeof(intel_dp->psr_dpcd));
-
-       drm_dp_dpcd_read(&intel_dp->aux, DP_PANEL_REPLAY_CAP_SUPPORT,
-                        &intel_dp->pr_dpcd, sizeof(intel_dp->pr_dpcd));
-
-       if (intel_dp->pr_dpcd[INTEL_PR_DPCD_INDEX(DP_PANEL_REPLAY_CAP_SUPPORT)] &
-           DP_PANEL_REPLAY_SUPPORT)
-               _panel_replay_init_dpcd(intel_dp);
+       _psr_init_dpcd(intel_dp);
 
-       if (intel_dp->psr_dpcd[0])
-               _psr_init_dpcd(intel_dp);
+       _panel_replay_init_dpcd(intel_dp);
 
        if (intel_dp->psr.sink_psr2_support ||
            intel_dp->psr.sink_panel_replay_su_support)