drm/nouveau/kms/nv50: initial support for DP 1.2 multi-stream

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_connector.c

@@ -1118,12 +1118,21 @@ nouveau_connector_hotplug(struct nvif_notify *notify)
 	struct nouveau_drm *drm = nouveau_drm(connector->dev);
 	const struct nvif_notify_conn_rep_v0 *rep = notify->data;
 	const char *name = connector->name;
+	struct nouveau_encoder *nv_encoder;
 
 	if (rep->mask & NVIF_NOTIFY_CONN_V0_IRQ) {
+		NV_DEBUG(drm, "service %s\n", name);
+		if ((nv_encoder = find_encoder(connector, DCB_OUTPUT_DP)))
+			nv50_mstm_service(nv_encoder->dp.mstm);
 	} else {
 		bool plugged = (rep->mask != NVIF_NOTIFY_CONN_V0_UNPLUG);
 
 		NV_DEBUG(drm, "%splugged %s\n", plugged ? "" : "un", name);
+		if ((nv_encoder = find_encoder(connector, DCB_OUTPUT_DP))) {
+			if (!plugged)
+				nv50_mstm_remove(nv_encoder->dp.mstm);
+		}
+
 		drm_helper_hpd_irq_event(connector->dev);
 	}
 

drivers/gpu/drm/nouveau/nouveau_dp.c

@@ -33,6 +33,10 @@
 #include <nvif/class.h>
 #include <nvif/cl5070.h>
 
+MODULE_PARM_DESC(mst, "Enable DisplayPort multi-stream (default: enabled)");
+static int nouveau_mst = 1;
+module_param_named(mst, nouveau_mst, int, 0400);
+
 static void
 nouveau_dp_probe_oui(struct drm_device *dev, struct nvkm_i2c_aux *aux, u8 *dpcd)
 {
@@ -88,7 +92,9 @@ nouveau_dp_detect(struct nouveau_encoder *nv_encoder)
 
 	nouveau_dp_probe_oui(dev, aux, dpcd);
 
-	ret = nv50_mstm_detect(nv_encoder->dp.mstm, dpcd, 0);
+	ret = nv50_mstm_detect(nv_encoder->dp.mstm, dpcd, nouveau_mst);
+	if (ret == 1)
+		return NOUVEAU_DP_MST;
 	if (ret == 0)
 		return NOUVEAU_DP_SST;
 	return ret;

drivers/gpu/drm/nouveau/nouveau_encoder.h

@@ -103,4 +103,6 @@ struct nouveau_connector *
 nouveau_encoder_connector_get(struct nouveau_encoder *encoder);
 
 int nv50_mstm_detect(struct nv50_mstm *, u8 dpcd[8], int allow);
+void nv50_mstm_remove(struct nv50_mstm *);
+void nv50_mstm_service(struct nv50_mstm *);
 #endif /* __NOUVEAU_ENCODER_H__ */