[PATCH v4 3/3] drm/i915/edp: eDP Data Overrride

[Suraj Kandpal]

We need override certain link rates in favour of the next available
higher link rate. The Link rates that need to be overridden are
indicated by a mask in VBT. To make sure these modes are skipped we
don't add them in them in the sink rates array.

--v2
-Update the link rates after we have a final set of link rates [Ankit]
-Break this patch up [Ankit]
-Optimize the assingment during loop [Ankit]

--v3
-Add protection against broken VBTs [Jani]

--v4
-Fix build errors
-Create a seprate function to check if edp data override is selected
and using the correct vbt

Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
---
 drivers/gpu/drm/i915/display/intel_bios.c | 17 +++++++++++++++--
 drivers/gpu/drm/i915/display/intel_bios.h |  2 ++
 drivers/gpu/drm/i915/display/intel_dp.c   | 22 ++++++++++++++++++++++
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index 7adb7c4b0432..5d9126a0219e 100644
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c
@@ -2519,12 +2519,25 @@ int intel_bios_dp_max_lane_count(const struct intel_bios_encoder_data *devdata)
 }
 
 bool
-intel_bios_encoder_supports_edp_rate(const struct intel_bios_encoder_data *devdata,
-				     int rate)
+intel_bios_vbt_supports_edp_data_override(const struct intel_bios_encoder_data *devdata)
 {
 	if (!devdata || devdata->display->vbt.version < 263)
 		return false;
 
+	/*
+	 * This means the VBT ends up asking us to override every possible rate
+	 * indicating the VBT is broken so skip this
+	 */
+	if (hweight32(devdata->child.edp_data_rate_override) >= 11)
+		return false;
+
+	return true;
+}
+
+bool
+intel_bios_encoder_supports_edp_rate(const struct intel_bios_encoder_data *devdata,
+				     int rate)
+{
 	return devdata->child.edp_data_rate_override & edp_rate_override_mask(rate);
 }
 
diff --git a/drivers/gpu/drm/i915/display/intel_bios.h b/drivers/gpu/drm/i915/display/intel_bios.h
index a4abaa89a682..d244caef2275 100644
--- a/drivers/gpu/drm/i915/display/intel_bios.h
+++ b/drivers/gpu/drm/i915/display/intel_bios.h
@@ -276,5 +276,7 @@ void intel_bios_for_each_encoder(struct intel_display *display,
 					      const struct intel_bios_encoder_data *devdata));
 
 void intel_bios_debugfs_register(struct intel_display *display);
+bool
+intel_bios_vbt_supports_edp_data_override(const struct intel_bios_encoder_data *devdata);
 
 #endif /* _INTEL_BIOS_H_ */
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 54d88f24b689..7e905e912aef 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -4277,6 +4277,26 @@ static void intel_edp_mso_init(struct intel_dp *intel_dp)
 	intel_dp->mso_pixel_overlap = mso ? info->mso_pixel_overlap : 0;
 }
 
+static void
+intel_edp_set_data_override_rates(struct intel_dp *intel_dp)
+{
+	struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
+	int *sink_rates = intel_dp->sink_rates;
+	int i, j = 0;
+
+	if (!intel_bios_vbt_supports_edp_data_override(encoder->devdata))
+		return;
+
+	for (i = 0; i < intel_dp->num_sink_rates; i++) {
+		if (intel_bios_encoder_supports_edp_rate(encoder->devdata,
+							 intel_dp->sink_rates[i]))
+			continue;
+
+		sink_rates[j++] = intel_dp->sink_rates[i];
+	}
+	intel_dp->num_sink_rates = j;
+}
+
 static void
 intel_edp_set_sink_rates(struct intel_dp *intel_dp)
 {
@@ -4327,6 +4347,8 @@ intel_edp_set_sink_rates(struct intel_dp *intel_dp)
 		intel_dp->use_rate_select = true;
 	else
 		intel_dp_set_sink_rates(intel_dp);
+
+	intel_edp_set_data_override_rates(intel_dp);
 }
 
 static bool
-- 
2.34.1