From dce5ed4af323f0674fe252fc5f60473a8c7c695f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Tue, 22 Mar 2022 14:00:05 +0200
Subject: drm/i915/dp: Respect the sink's max TMDS clock when dealing with
 DP->HDMI DFPs
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Git-commit: 069b78f5d1d3888fb6903822efbc087a82303ceb
Patch-mainline: v5.19-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

Currently we only look at the DFPs max TMDS clock limit when
considering whether the mode is valid, or whether we can do
deep color. The sink's max TMDS clock limit may be lower than
the DFPs, so we need to account for it as well.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4095
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2844
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220322120015.28074-3-ville.syrjala@linux.intel.com
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 95c13a428088..2ef14583c00e 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -829,20 +829,34 @@ static bool intel_dp_hdisplay_bad(struct drm_i915_private *dev_priv,
 	return hdisplay == 4096 && !HAS_DDI(dev_priv);
 }
 
+static int intel_dp_max_tmds_clock(struct intel_dp *intel_dp)
+{
+	struct intel_connector *connector = intel_dp->attached_connector;
+	const struct drm_display_info *info = &connector->base.display_info;
+	int max_tmds_clock = intel_dp->dfp.max_tmds_clock;
+
+	/* Only consider the sink's max TMDS clock if we know this is a HDMI DFP */
+	if (max_tmds_clock && info->max_tmds_clock)
+		max_tmds_clock = min(max_tmds_clock, info->max_tmds_clock);
+
+	return max_tmds_clock;
+}
+
 static enum drm_mode_status
 intel_dp_tmds_clock_valid(struct intel_dp *intel_dp,
 			  int clock, int bpc, bool ycbcr420_output)
 {
-	int tmds_clock;
+	int tmds_clock, min_tmds_clock, max_tmds_clock;
 
 	tmds_clock = intel_hdmi_tmds_clock(clock, bpc, ycbcr420_output);
 
-	if (intel_dp->dfp.min_tmds_clock &&
-	    tmds_clock < intel_dp->dfp.min_tmds_clock)
+	min_tmds_clock = intel_dp->dfp.min_tmds_clock;
+	max_tmds_clock = intel_dp_max_tmds_clock(intel_dp);
+
+	if (min_tmds_clock && tmds_clock < min_tmds_clock)
 		return MODE_CLOCK_LOW;
 
-	if (intel_dp->dfp.max_tmds_clock &&
-	    tmds_clock > intel_dp->dfp.max_tmds_clock)
+	if (max_tmds_clock && tmds_clock > max_tmds_clock)
 		return MODE_CLOCK_HIGH;
 
 	return MODE_OK;
-- 
2.38.1