Clarify the conditions for choosing the MST mode to use by adding a new
function intel_dp_mst_mode_choose(). This also prepares for being able
to extend the MST modes to single-stream sideband messaging.
Cc: Arun R Murthy <arun.r.murthy@xxxxxxxxx>
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_dp.c | 25 +++++++++++++++++++------
1 file changed, 19 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 9590c8c2c4f3..127b5a89502d 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -4049,6 +4049,24 @@ static const char *intel_dp_mst_mode_str(enum drm_dp_mst_mode mst_mode)
return "SST";
}
+static enum drm_dp_mst_mode
+intel_dp_mst_mode_choose(struct intel_dp *intel_dp,
+ enum drm_dp_mst_mode sink_mst_mode)
+{
+ struct drm_i915_private *i915 = dp_to_i915(intel_dp);
+
+ if (!i915->display.params.enable_dp_mst)
+ return DRM_DP_SST;
+
+ if (!intel_dp_mst_source_support(intel_dp))
+ return DRM_DP_SST;
+
+ if (sink_mst_mode == DRM_DP_SST_SIDEBAND_MSG)
+ return DRM_DP_SST;
+
+ return sink_mst_mode;
+}
+
static enum drm_dp_mst_mode
intel_dp_mst_detect(struct intel_dp *intel_dp)
{
@@ -4059,12 +4077,7 @@ intel_dp_mst_detect(struct intel_dp *intel_dp)
sink_mst_mode = drm_dp_read_mst_cap(&intel_dp->aux, intel_dp->dpcd);
- if (i915->display.params.enable_dp_mst &&
- intel_dp_mst_source_support(intel_dp) &&
- sink_mst_mode == DRM_DP_MST)
- mst_detect = DRM_DP_MST;
- else
- mst_detect = DRM_DP_SST;
+ mst_detect = intel_dp_mst_mode_choose(intel_dp, sink_mst_mode);
drm_dbg_kms(&i915->drm,
"[ENCODER:%d:%s] MST support: port: %s, sink: %s, modparam: %s -> enable: %s\n",
--
2.39.2
