Merge tag 'drm-misc-next-2021-03-03' of git://anongit.freedesktop.org/drm/drm-misc...

[sfrench/cifs-2.6.git] / drivers / gpu / drm / drm_dp_mst_topology.c

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index f1068c5bcef842904fe37a636e98f60a1de1911d..42a0c6888c338a5202e806648eb421d0c9a0dd7f 100644 (file)
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -3635,14 +3635,26 @@ static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
        return 0;
 }
 
-static int drm_dp_get_vc_payload_bw(u8 dp_link_bw, u8  dp_link_count)
+/**
+ * drm_dp_get_vc_payload_bw - get the VC payload BW for an MST link
+ * @link_rate: link rate in 10kbits/s units
+ * @link_lane_count: lane count
+ *
+ * Calculate the total bandwidth of a MultiStream Transport link. The returned
+ * value is in units of PBNs/(timeslots/1 MTP). This value can be used to
+ * convert the number of PBNs required for a given stream to the number of
+ * timeslots this stream requires in each MTP.
+ */
+int drm_dp_get_vc_payload_bw(int link_rate, int link_lane_count)
 {
-       if (dp_link_bw == 0 || dp_link_count == 0)
-               DRM_DEBUG_KMS("invalid link bandwidth in DPCD: %x (link count: %d)\n",
-                             dp_link_bw, dp_link_count);
+       if (link_rate == 0 || link_lane_count == 0)
+               DRM_DEBUG_KMS("invalid link rate/lane count: (%d / %d)\n",
+                             link_rate, link_lane_count);
 
-       return dp_link_bw * dp_link_count / 2;
+       /* See DP v2.0 2.6.4.2, VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */
+       return link_rate * link_lane_count / 54000;
 }
+EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
 
 /**
  * drm_dp_read_mst_cap() - check whether or not a sink supports MST
@@ -3698,7 +3710,7 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
                        goto out_unlock;
                }
 
-               mgr->pbn_div = drm_dp_get_vc_payload_bw(mgr->dpcd[1],
+               mgr->pbn_div = drm_dp_get_vc_payload_bw(drm_dp_bw_code_to_link_rate(mgr->dpcd[1]),
                                                        mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK);
                if (mgr->pbn_div == 0) {
                        ret = -EINVAL;
@@ -4218,6 +4230,7 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
 
        switch (port->pdt) {
        case DP_PEER_DEVICE_NONE:
+               break;
        case DP_PEER_DEVICE_MST_BRANCHING:
                if (!port->mcs)
                        ret = connector_status_connected;
@@ -5834,8 +5847,7 @@ struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
        if (drm_dp_read_desc(port->mgr->aux, &desc, true))
                return NULL;
 
-       if (drm_dp_has_quirk(&desc, 0,
-                            DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) &&
+       if (drm_dp_has_quirk(&desc, DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) &&
            port->mgr->dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14 &&
            port->parent == port->mgr->mst_primary) {
                u8 downstreamport;