drm/i915/mst: use the MST mode detected previously

Drop the duplicate read of DP_MSTM_CAP DPCD register, and the duplicate
logic for choosing MST mode, and store the chosen mode in struct
intel_dp. Rename intel_dp_configure_mst() to intel_dp_mst_configure()
while at it.

v2: Rebase on drm_dp_mst_detect() returning the mode, not bool

Cc: Arun R Murthy <arun.r.murthy@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/93a48df9a77e1138bb28e645fae3f9c79b094cc7.1710839496.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 8b9860cefaae88c01316bb2891f76773ff2cc98b..8a35fb6b2ade312f327afc2dd267476719511c28 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1804,6 +1804,7 @@ struct intel_dp {
 
        bool is_mst;
        int active_mst_links;
+       enum drm_dp_mst_mode mst_detect;
 
        /* connector directly attached - won't be use for modeset in mst world */
        struct intel_connector *attached_connector;

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index c253be068e5155d55200590ed4df594b7726df08..ee51985c3d15559f304ff8544fa674a33deaf693 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -4091,19 +4091,17 @@ intel_dp_mst_detect(struct intel_dp *intel_dp)
 }
 
 static void
-intel_dp_configure_mst(struct intel_dp *intel_dp)
+intel_dp_mst_configure(struct intel_dp *intel_dp)
 {
-       struct drm_i915_private *i915 = dp_to_i915(intel_dp);
-       bool sink_can_mst = drm_dp_read_mst_cap(&intel_dp->aux, intel_dp->dpcd) == DRM_DP_MST;
-
        if (!intel_dp_mst_source_support(intel_dp))
                return;
 
-       intel_dp->is_mst = sink_can_mst &&
-               i915->display.params.enable_dp_mst;
+       intel_dp->is_mst = intel_dp->mst_detect != DRM_DP_SST;
 
-       drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr,
-                                       intel_dp->is_mst);
+       drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr, intel_dp->is_mst);
+
+       /* Avoid stale info on the next detect cycle. */
+       intel_dp->mst_detect = DRM_DP_SST;
 }
 
 static bool
@@ -5452,7 +5450,6 @@ intel_dp_detect_dpcd(struct intel_dp *intel_dp)
 {
        struct drm_i915_private *i915 = dp_to_i915(intel_dp);
        struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
-       enum drm_dp_mst_mode mst_detect;
        u8 *dpcd = intel_dp->dpcd;
        u8 type;
 
@@ -5464,7 +5461,7 @@ intel_dp_detect_dpcd(struct intel_dp *intel_dp)
        if (!intel_dp_get_dpcd(intel_dp))
                return connector_status_disconnected;
 
-       mst_detect = intel_dp_mst_detect(intel_dp);
+       intel_dp->mst_detect = intel_dp_mst_detect(intel_dp);
 
        /* if there's no downstream port, we're done */
        if (!drm_dp_is_branch(dpcd))
@@ -5477,7 +5474,7 @@ intel_dp_detect_dpcd(struct intel_dp *intel_dp)
                connector_status_connected : connector_status_disconnected;
        }
 
-       if (mst_detect == DRM_DP_MST)
+       if (intel_dp->mst_detect == DRM_DP_MST)
                return connector_status_connected;
 
        /* If no HPD, poke DDC gently */
@@ -5809,7 +5806,7 @@ intel_dp_detect(struct drm_connector *connector,
 
        intel_dp_detect_dsc_caps(intel_dp, intel_connector);
 
-       intel_dp_configure_mst(intel_dp);
+       intel_dp_mst_configure(intel_dp);
 
        /*
         * TODO: Reset link params when switching to MST mode, until MST