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* [PATCH] drm/i915/dp: Add a meaningful return to intel_dp_read_dsc_dpcd
@ 2026-01-28  4:49 Suraj Kandpal
  2026-01-28  6:09 ` ✓ i915.CI.BAT: success for " Patchwork
                   ` (8 more replies)
  0 siblings, 9 replies; 13+ messages in thread
From: Suraj Kandpal @ 2026-01-28  4:49 UTC (permalink / raw)
  To: intel-xe, intel-gfx; +Cc: ankit.k.nautiyal, arun.r.murthy, Suraj Kandpal

Add a meaningful return to intel_dp_read_dsc_dpcd so tha we avoid
unwanted DPCD reads which are not needed once we know DSC DPCD
read fails. While we are at it remove the drm_err since we do not
shout error during intel_dp_detect phase since it may take time
to come up after pps_on is called for eDP scenario.

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 79fd3b8d8b25..d2ed8ec145a2 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -4281,20 +4281,21 @@ static bool intel_dp_get_colorimetry_status(struct intel_dp *intel_dp)
 	return dprx & DP_VSC_SDP_EXT_FOR_COLORIMETRY_SUPPORTED;
 }
 
-static void intel_dp_read_dsc_dpcd(struct drm_dp_aux *aux,
-				   u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])
+static int intel_dp_read_dsc_dpcd(struct drm_dp_aux *aux,
+				  u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])
 {
 	if (drm_dp_dpcd_read(aux, DP_DSC_SUPPORT, dsc_dpcd,
 			     DP_DSC_RECEIVER_CAP_SIZE) < 0) {
-		drm_err(aux->drm_dev,
-			"Failed to read DPCD register 0x%x\n",
-			DP_DSC_SUPPORT);
-		return;
+		drm_dbg_kms(aux->drm_dev,
+			    "Could not read DSC DPCD register 0x%x\n",
+			    DP_DSC_SUPPORT);
+		return -EINVAL;
 	}
 
 	drm_dbg_kms(aux->drm_dev, "DSC DPCD: %*ph\n",
 		    DP_DSC_RECEIVER_CAP_SIZE,
 		    dsc_dpcd);
+	return 0;
 }
 
 static void init_dsc_overall_throughput_limits(struct intel_connector *connector, bool is_branch)
@@ -4345,8 +4346,11 @@ void intel_dp_get_dsc_sink_cap(u8 dpcd_rev,
 	if (dpcd_rev < DP_DPCD_REV_14)
 		return;
 
-	intel_dp_read_dsc_dpcd(connector->dp.dsc_decompression_aux,
-			       connector->dp.dsc_dpcd);
+	if (intel_dp_read_dsc_dpcd(connector->dp.dsc_decompression_aux,
+				   connector->dp.dsc_dpcd) < 0) {
+		drm_err(display->drm, "Failed to read DSC DPCD register\n");
+		return;
+	}
 
 	if (drm_dp_dpcd_readb(connector->dp.dsc_decompression_aux, DP_FEC_CAPABILITY,
 			      &connector->dp.fec_capability) < 0) {
@@ -4376,7 +4380,9 @@ static void intel_edp_get_dsc_sink_cap(u8 edp_dpcd_rev, struct intel_connector *
 	if (edp_dpcd_rev < DP_EDP_14)
 		return;
 
-	intel_dp_read_dsc_dpcd(connector->dp.dsc_decompression_aux, connector->dp.dsc_dpcd);
+	if (intel_dp_read_dsc_dpcd(connector->dp.dsc_decompression_aux,
+				   connector->dp.dsc_dpcd) < 0)
+		return;
 
 	if (connector->dp.dsc_dpcd[0] & DP_DSC_DECOMPRESSION_IS_SUPPORTED)
 		init_dsc_overall_throughput_limits(connector, false);
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2026-02-03  0:54 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-01-28  4:49 [PATCH] drm/i915/dp: Add a meaningful return to intel_dp_read_dsc_dpcd Suraj Kandpal
2026-01-28  6:09 ` ✓ i915.CI.BAT: success for " Patchwork
2026-01-28 11:08 ` [PATCH] " Jani Nikula
2026-01-29  4:13   ` Kandpal, Suraj
2026-01-28 12:35 ` ✓ i915.CI.Full: success for " Patchwork
2026-01-29  4:18 ` [PATCH v2] " Suraj Kandpal
2026-02-02  8:00   ` Nautiyal, Ankit K
2026-01-29  4:59 ` ✓ i915.CI.BAT: success for drm/i915/dp: Add a meaningful return to intel_dp_read_dsc_dpcd (rev2) Patchwork
2026-01-29  7:06 ` ✗ i915.CI.Full: failure " Patchwork
2026-02-02  8:18 ` [PATCH v3] drm/i915/dp: Add a meaningful return to intel_dp_read_dsc_dpcd Suraj Kandpal
2026-02-02  8:47   ` Nautiyal, Ankit K
2026-02-02 19:47 ` ✓ i915.CI.BAT: success for drm/i915/dp: Add a meaningful return to intel_dp_read_dsc_dpcd (rev3) Patchwork
2026-02-03  0:54 ` ✗ i915.CI.Full: failure " Patchwork

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