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* [PATCH] drm/i915/dp: On DPCD init/caps wake the DPRx
@ 2026-02-19  9:43 Arun R Murthy
  2026-02-19 10:45 ` ✗ CI.checkpatch: warning for " Patchwork
                   ` (10 more replies)
  0 siblings, 11 replies; 24+ messages in thread
From: Arun R Murthy @ 2026-02-19  9:43 UTC (permalink / raw)
  To: intel-gfx, intel-xe; +Cc: imre.deak, suraj.kandpal, Arun R Murthy

Before reading the DPCD caps for eDP wake the sink device and for DP
after reading the lttpr caps and before reading the dpcd caps wake up
the sink device.

Closes: https://issues.redhat.com/browse/RHEL-120913
Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c       | 41 +++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_dp.h       |  1 +
 .../drm/i915/display/intel_dp_link_training.c |  3 ++
 3 files changed, 45 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 454e6144ee4e..2fbb947e6cc8 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -4705,6 +4705,45 @@ intel_edp_set_sink_rates(struct intel_dp *intel_dp)
 	intel_edp_set_data_override_rates(intel_dp);
 }
 
+void intel_dp_wake_sink(struct intel_dp *intel_dp)
+{
+	u8 value = 0;
+	int ret = 0, try = 0;
+
+	intel_dp_dpcd_set_probe(intel_dp, false);
+
+	/*
+	 * Wake the sink device
+	 * Spec DP2.1 section 2.3.1.2 if AUX CH is powered down by writing 0x02
+	 * to DP_SET_POWER dpcd reg, 1ms time would be required to wake it up
+	 */
+	while (try < 10 && ret < 0) {
+		ret = drm_dp_dpcd_readb(&intel_dp->aux, DP_SET_POWER, &value);
+		/*
+		 * If sink is in D3 then it may not respond to the AUX tx so
+		 * wake it up to D3_AUX_ON state
+		 */
+		if (value == DP_SET_POWER_D3) {
+			/* After setting to D0 need a min of 1ms to wake(Spec DP2.1 sec 2.3.1.2) */
+			drm_dp_dpcd_writeb(&intel_dp->aux, DP_SET_POWER,
+					   DP_SET_POWER_D0);
+			fsleep(1000);
+			drm_dp_dpcd_writeb(&intel_dp->aux, DP_SET_POWER,
+					   DP_SET_POWER_D3_AUX_ON);
+			break;
+		} else if ((value == DP_SET_POWER_D0) ||
+			   (value == DP_SET_POWER_D3_AUX_ON)) {
+			/* if in D0 or D3_AUX_ON exit */
+			break;
+		}
+		/* Sink in D0 or even if read fails a minimum of 1ms is required to wake and respond */
+		fsleep(1000);
+		try++;
+	}
+
+	intel_dp_dpcd_set_probe(intel_dp, true);
+}
+
 static bool
 intel_edp_init_dpcd(struct intel_dp *intel_dp, struct intel_connector *connector)
 {
@@ -4713,6 +4752,8 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp, struct intel_connector *connector
 	/* this function is meant to be called only once */
 	drm_WARN_ON(display->drm, intel_dp->dpcd[DP_DPCD_REV] != 0);
 
+	intel_dp_wake_sink(intel_dp);
+
 	if (drm_dp_read_dpcd_caps(&intel_dp->aux, intel_dp->dpcd) != 0)
 		return false;
 
diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
index b0bbd5981f57..3f16077c0cc7 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.h
+++ b/drivers/gpu/drm/i915/display/intel_dp.h
@@ -232,6 +232,7 @@ bool intel_dp_dotclk_valid(struct intel_display *display,
 bool intel_dp_joiner_candidate_valid(struct intel_connector *connector,
 				     int hdisplay,
 				     int num_joined_pipes);
+void intel_dp_wake_sink(struct intel_dp *intel_dp);
 
 #define for_each_joiner_candidate(__connector, __mode, __num_joined_pipes) \
 	for ((__num_joined_pipes) = 1; (__num_joined_pipes) <= (I915_MAX_PIPES); (__num_joined_pipes)++) \
diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index 54c585c59b90..cbb712ea9f60 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -270,6 +270,9 @@ int intel_dp_init_lttpr_and_dprx_caps(struct intel_dp *intel_dp)
 		lttpr_count = intel_dp_init_lttpr(intel_dp, dpcd);
 	}
 
+	/* After reading LTTPR wake up the sink before reading DPRX caps */
+	intel_dp_wake_sink(intel_dp);
+
 	/*
 	 * The DPTX shall read the DPRX caps after LTTPR detection, so re-read
 	 * it here.
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 24+ messages in thread
end of thread, other threads:[~2026-03-10  8:53 UTC | newest]

Thread overview: 24+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-02-19  9:43 [PATCH] drm/i915/dp: On DPCD init/caps wake the DPRx Arun R Murthy
2026-02-19 10:45 ` ✗ CI.checkpatch: warning for " Patchwork
2026-02-19 10:46 ` ✓ CI.KUnit: success " Patchwork
2026-02-19 11:22 ` ✓ Xe.CI.BAT: " Patchwork
2026-02-19 14:20 ` ✗ Xe.CI.FULL: failure " Patchwork
2026-02-19 14:53 ` [PATCH] " Ville Syrjälä
2026-02-19 15:12   ` Murthy, Arun R
2026-02-20  3:11     ` Ville Syrjälä
2026-02-20  5:01       ` Murthy, Arun R
2026-02-24  8:24         ` Ville Syrjälä
2026-02-24  8:48           ` Murthy, Arun R
2026-02-24  7:48 ` [PATCHv2] " Arun R Murthy
2026-02-24 14:50   ` Imre Deak
2026-02-25  3:33     ` Murthy, Arun R
2026-02-25  5:58       ` Murthy, Arun R
2026-03-02  7:57       ` Imre Deak
2026-03-02  9:04         ` Murthy, Arun R
2026-03-02  9:20           ` Imre Deak
2026-03-10  8:52             ` Murthy, Arun R
2026-02-24  7:56 ` ✓ CI.KUnit: success for drm/i915/dp: On DPCD init/caps wake the DPRx (rev2) Patchwork
2026-02-25  6:11 ` [PATCHv3] drm/i915/dp: On DPCD init wake the DPRx for eDP Arun R Murthy
2026-02-25  6:19 ` ✓ CI.KUnit: success for drm/i915/dp: On DPCD init/caps wake the DPRx (rev3) Patchwork
2026-02-25  6:56 ` ✓ Xe.CI.BAT: " Patchwork
2026-02-25 11:20 ` ✗ Xe.CI.FULL: failure " Patchwork

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