[PATCH v8 12/12] drm/i915: Check TMDS clock DP to HDMI dongle

[Mika Kahola]

Respect max TMDS clock frequency from DPCD for active
DP to HDMI adapters.

Signed-off-by: Mika Kahola <mika.kahola at intel.com>
---
 drivers/gpu/drm/i915/intel_drv.h  |  3 +++
 drivers/gpu/drm/i915/intel_hdmi.c | 27 +++++++++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 1c700b0..b7fd551 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -817,6 +817,9 @@ struct intel_hdmi {
 	i915_reg_t hdmi_reg;
 	int ddc_bus;
 	struct {
+		int max_tmds_clock;
+	} dp_to_hdmi;
+	struct {
 		enum drm_dp_dual_mode_type type;
 		int max_tmds_clock;
 	} dp_dual_mode;
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 4df9f38..1469d00 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1204,6 +1204,9 @@ static int hdmi_port_clock_limit(struct intel_hdmi *hdmi,
 	int max_tmds_clock = intel_hdmi_source_max_tmds_clock(to_i915(dev));
 
 	if (respect_downstream_limits) {
+		if (hdmi->dp_to_hdmi.max_tmds_clock)
+			max_tmds_clock = min(max_tmds_clock,
+					     hdmi->dp_to_hdmi.max_tmds_clock);
 		if (hdmi->dp_dual_mode.max_tmds_clock)
 			max_tmds_clock = min(max_tmds_clock,
 					     hdmi->dp_dual_mode.max_tmds_clock);
@@ -1373,11 +1376,33 @@ intel_hdmi_unset_edid(struct drm_connector *connector)
 	intel_hdmi->dp_dual_mode.type = DRM_DP_DUAL_MODE_NONE;
 	intel_hdmi->dp_dual_mode.max_tmds_clock = 0;
 
+	intel_hdmi->dp_to_hdmi.max_tmds_clock = 0;
+
 	kfree(to_intel_connector(connector)->detect_edid);
 	to_intel_connector(connector)->detect_edid = NULL;
 }
 
 static void
+intel_hdmi_dp_adapter_detect(struct drm_connector *connector)
+{
+	struct intel_hdmi *intel_hdmi = intel_attached_hdmi(connector);
+	struct intel_digital_port *intel_dig_port =
+		hdmi_to_dig_port(intel_hdmi);
+	struct intel_dp *intel_dp = &intel_dig_port->dp;
+	int type = intel_dp->downstream_ports[0] & DP_DS_PORT_TYPE_MASK;
+
+	if (type != DP_DS_PORT_TYPE_HDMI)
+		return;
+
+	intel_hdmi->dp_to_hdmi.max_tmds_clock =
+		drm_dp_downstream_max_clock(intel_dp->dpcd,
+					    intel_dp->downstream_ports);
+
+	DRM_DEBUG_KMS("DP HDMI adaptor detected (max TMDS clock : %d kHz\n",
+		      intel_hdmi->dp_to_hdmi.max_tmds_clock);
+}
+
+static void
 intel_hdmi_dp_dual_mode_detect(struct drm_connector *connector, bool has_edid)
 {
 	struct drm_i915_private *dev_priv = to_i915(connector->dev);
@@ -1438,6 +1463,8 @@ intel_hdmi_set_edid(struct drm_connector *connector, bool force)
 
 		intel_hdmi_dp_dual_mode_detect(connector, edid != NULL);
 
+		intel_hdmi_dp_adapter_detect(connector);
+
 		intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS);
 	}
 
-- 
1.9.1