--- /dev/null
+
+#include <drm/drmP.h>
+#include <drm/drm_dp_mst_helper.h>
+#include <drm/drm_fb_helper.h>
+
+#include "radeon.h"
+#include "atom.h"
+#include "ni_reg.h"
+
+static struct radeon_encoder *radeon_dp_create_fake_mst_encoder(struct radeon_connector *connector);
+
+static int radeon_atom_set_enc_offset(int id)
+{
+       static const int offsets[] = { EVERGREEN_CRTC0_REGISTER_OFFSET,
+                                      EVERGREEN_CRTC1_REGISTER_OFFSET,
+                                      EVERGREEN_CRTC2_REGISTER_OFFSET,
+                                      EVERGREEN_CRTC3_REGISTER_OFFSET,
+                                      EVERGREEN_CRTC4_REGISTER_OFFSET,
+                                      EVERGREEN_CRTC5_REGISTER_OFFSET,
+                                      0x13830 - 0x7030 };
+
+       return offsets[id];
+}
+
+static int radeon_dp_mst_set_be_cntl(struct radeon_encoder *primary,
+                                    struct radeon_encoder_mst *mst_enc,
+                                    enum radeon_hpd_id hpd, bool enable)
+{
+       struct drm_device *dev = primary->base.dev;
+       struct radeon_device *rdev = dev->dev_private;
+       uint32_t reg;
+       int retries = 0;
+       uint32_t temp;
+
+       reg = RREG32(NI_DIG_BE_CNTL + primary->offset);
+
+       /* set MST mode */
+       reg &= ~NI_DIG_FE_DIG_MODE(7);
+       reg |= NI_DIG_FE_DIG_MODE(NI_DIG_MODE_DP_MST);
+
+       if (enable)
+               reg |= NI_DIG_FE_SOURCE_SELECT(1 << mst_enc->fe);
+       else
+               reg &= ~NI_DIG_FE_SOURCE_SELECT(1 << mst_enc->fe);
+
+       reg |= NI_DIG_HPD_SELECT(hpd);
+       DRM_DEBUG_KMS("writing 0x%08x 0x%08x\n", NI_DIG_BE_CNTL + primary->offset, reg);
+       WREG32(NI_DIG_BE_CNTL + primary->offset, reg);
+
+       if (enable) {
+               uint32_t offset = radeon_atom_set_enc_offset(mst_enc->fe);
+
+               do {
+                       temp = RREG32(NI_DIG_FE_CNTL + offset);
+               } while ((temp & NI_DIG_SYMCLK_FE_ON) && retries++ < 10000);
+               if (retries == 10000)
+                       DRM_ERROR("timed out waiting for FE %d %d\n", primary->offset, mst_enc->fe);
+       }
+       return 0;
+}
+
+static int radeon_dp_mst_set_stream_attrib(struct radeon_encoder *primary,
+                                          int stream_number,
+                                          int fe,
+                                          int slots)
+{
+       struct drm_device *dev = primary->base.dev;
+       struct radeon_device *rdev = dev->dev_private;
+       u32 temp, val;
+       int retries  = 0;
+       int satreg, satidx;
+
+       satreg = stream_number >> 1;
+       satidx = stream_number & 1;
+
+       temp = RREG32(NI_DP_MSE_SAT0 + satreg + primary->offset);
+
+       val = NI_DP_MSE_SAT_SLOT_COUNT0(slots) | NI_DP_MSE_SAT_SRC0(fe);
+
+       val <<= (16 * satidx);
+
+       temp &= ~(0xffff << (16 * satidx));
+
+       temp |= val;
+
+       DRM_DEBUG_KMS("writing 0x%08x 0x%08x\n", NI_DP_MSE_SAT0 + satreg + primary->offset, temp);
+       WREG32(NI_DP_MSE_SAT0 + satreg + primary->offset, temp);
+
+       WREG32(NI_DP_MSE_SAT_UPDATE + primary->offset, 1);
+
+       do {
+               temp = RREG32(NI_DP_MSE_SAT_UPDATE + primary->offset);
+       } while ((temp & 0x1) && retries++ < 10000);
+
+       if (retries == 10000)
+               DRM_ERROR("timed out waitin for SAT update %d\n", primary->offset);
+
+       /* MTP 16 ? */
+       return 0;
+}
+
+static int radeon_dp_mst_update_stream_attribs(struct radeon_connector *mst_conn,
+                                              struct radeon_encoder *primary)
+{
+       struct drm_device *dev = mst_conn->base.dev;
+       struct stream_attribs new_attribs[6];
+       int i;
+       int idx = 0;
+       struct radeon_connector *radeon_connector;
+       struct drm_connector *connector;
+
+       memset(new_attribs, 0, sizeof(new_attribs));
+       list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+               struct radeon_encoder *subenc;
+               struct radeon_encoder_mst *mst_enc;
+
+               radeon_connector = to_radeon_connector(connector);
+               if (!radeon_connector->is_mst_connector)
+                       continue;
+
+               if (radeon_connector->mst_port != mst_conn)
+                       continue;
+
+               subenc = radeon_connector->mst_encoder;
+               mst_enc = subenc->enc_priv;
+
+               if (!mst_enc->enc_active)
+                       continue;
+
+               new_attribs[idx].fe = mst_enc->fe;
+               new_attribs[idx].slots = drm_dp_mst_get_vcpi_slots(&mst_conn->mst_mgr, mst_enc->port);
+               idx++;
+       }
+
+       for (i = 0; i < idx; i++) {
+               if (new_attribs[i].fe != mst_conn->cur_stream_attribs[i].fe ||
+                   new_attribs[i].slots != mst_conn->cur_stream_attribs[i].slots) {
+                       radeon_dp_mst_set_stream_attrib(primary, i, new_attribs[i].fe, new_attribs[i].slots);
+                       mst_conn->cur_stream_attribs[i].fe = new_attribs[i].fe;
+                       mst_conn->cur_stream_attribs[i].slots = new_attribs[i].slots;
+               }
+       }
+
+       for (i = idx; i < mst_conn->enabled_attribs; i++) {
+               radeon_dp_mst_set_stream_attrib(primary, i, 0, 0);
+               mst_conn->cur_stream_attribs[i].fe = 0;
+               mst_conn->cur_stream_attribs[i].slots = 0;
+       }
+       mst_conn->enabled_attribs = idx;
+       return 0;
+}
+
+static int radeon_dp_mst_set_vcp_size(struct radeon_encoder *mst, uint32_t x, uint32_t y)
+{
+       struct drm_device *dev = mst->base.dev;
+       struct radeon_device *rdev = dev->dev_private;
+       struct radeon_encoder_mst *mst_enc = mst->enc_priv;
+       uint32_t val, temp;
+       uint32_t offset = radeon_atom_set_enc_offset(mst_enc->fe);
+       int retries = 0;
+
+       val = NI_DP_MSE_RATE_X(x) | NI_DP_MSE_RATE_Y(y);
+
+       WREG32(NI_DP_MSE_RATE_CNTL + offset, val);
+
+       do {
+               temp = RREG32(NI_DP_MSE_RATE_UPDATE + offset);
+       } while ((temp & 0x1) && (retries++ < 10000));
+
+       if (retries >= 10000)
+               DRM_ERROR("timed out wait for rate cntl %d\n", mst_enc->fe);
+       return 0;
+}
+
+static int radeon_dp_mst_get_ddc_modes(struct drm_connector *connector)
+{
+       struct radeon_connector *radeon_connector = to_radeon_connector(connector);
+       struct radeon_connector *master = radeon_connector->mst_port;
+       struct edid *edid;
+       int ret = 0;
+
+       edid = drm_dp_mst_get_edid(connector, &master->mst_mgr, radeon_connector->port);
+       radeon_connector->edid = edid;
+       DRM_DEBUG_KMS("edid retrieved %p\n", edid);
+       if (radeon_connector->edid) {
+               drm_mode_connector_update_edid_property(&radeon_connector->base, radeon_connector->edid);
+               ret = drm_add_edid_modes(&radeon_connector->base, radeon_connector->edid);
+               drm_edid_to_eld(&radeon_connector->base, radeon_connector->edid);
+               return ret;
+       }
+       drm_mode_connector_update_edid_property(&radeon_connector->base, NULL);
+
+       return ret;
+}
+
+static int radeon_dp_mst_get_modes(struct drm_connector *connector)
+{
+       return radeon_dp_mst_get_ddc_modes(connector);
+}
+
+static enum drm_mode_status
+radeon_dp_mst_mode_valid(struct drm_connector *connector,
+                       struct drm_display_mode *mode)
+{
+       /* TODO - validate mode against available PBN for link */
+       if (mode->clock < 10000)
+               return MODE_CLOCK_LOW;
+
+       if (mode->flags & DRM_MODE_FLAG_DBLCLK)
+               return MODE_H_ILLEGAL;
+
+       return MODE_OK;
+}
+
+struct drm_encoder *radeon_mst_best_encoder(struct drm_connector *connector)
+{
+       struct radeon_connector *radeon_connector = to_radeon_connector(connector);
+
+       return &radeon_connector->mst_encoder->base;
+}
+
+static const struct drm_connector_helper_funcs radeon_dp_mst_connector_helper_funcs = {
+       .get_modes = radeon_dp_mst_get_modes,
+       .mode_valid = radeon_dp_mst_mode_valid,
+       .best_encoder = radeon_mst_best_encoder,
+};
+
+static enum drm_connector_status
+radeon_dp_mst_detect(struct drm_connector *connector, bool force)
+{
+       struct radeon_connector *radeon_connector = to_radeon_connector(connector);
+       struct radeon_connector *master = radeon_connector->mst_port;
+
+       return drm_dp_mst_detect_port(connector, &master->mst_mgr, radeon_connector->port);
+}
+
+static void
+radeon_dp_mst_connector_destroy(struct drm_connector *connector)
+{
+       struct radeon_connector *radeon_connector = to_radeon_connector(connector);
+       struct radeon_encoder *radeon_encoder = radeon_connector->mst_encoder;
+
+       drm_encoder_cleanup(&radeon_encoder->base);
+       kfree(radeon_encoder);
+       drm_connector_cleanup(connector);
+       kfree(radeon_connector);
+}
+
+static void radeon_connector_dpms(struct drm_connector *connector, int mode)
+{
+       DRM_DEBUG_KMS("\n");
+}
+
+static const struct drm_connector_funcs radeon_dp_mst_connector_funcs = {
+       .dpms = radeon_connector_dpms,
+       .detect = radeon_dp_mst_detect,
+       .fill_modes = drm_helper_probe_single_connector_modes,
+       .destroy = radeon_dp_mst_connector_destroy,
+};
+
+static struct drm_connector *radeon_dp_add_mst_connector(struct drm_dp_mst_topology_mgr *mgr,
+                                                        struct drm_dp_mst_port *port,
+                                                        const char *pathprop)
+{
+       struct radeon_connector *master = container_of(mgr, struct radeon_connector, mst_mgr);
+       struct drm_device *dev = master->base.dev;
+       struct radeon_device *rdev = dev->dev_private;
+       struct radeon_connector *radeon_connector;
+       struct drm_connector *connector;
+
+       radeon_connector = kzalloc(sizeof(*radeon_connector), GFP_KERNEL);
+       if (!radeon_connector)
+               return NULL;
+
+       radeon_connector->is_mst_connector = true;
+       connector = &radeon_connector->base;
+       radeon_connector->port = port;
+       radeon_connector->mst_port = master;
+       DRM_DEBUG_KMS("\n");
+
+       drm_connector_init(dev, connector, &radeon_dp_mst_connector_funcs, DRM_MODE_CONNECTOR_DisplayPort);
+       drm_connector_helper_add(connector, &radeon_dp_mst_connector_helper_funcs);
+       radeon_connector->mst_encoder = radeon_dp_create_fake_mst_encoder(master);
+
+       drm_object_attach_property(&connector->base, dev->mode_config.path_property, 0);
+       drm_mode_connector_set_path_property(connector, pathprop);
+       drm_reinit_primary_mode_group(dev);
+
+       mutex_lock(&dev->mode_config.mutex);
+       radeon_fb_add_connector(rdev, connector);
+       mutex_unlock(&dev->mode_config.mutex);
+
+       drm_connector_register(connector);
+       return connector;
+}
+
+static void radeon_dp_destroy_mst_connector(struct drm_dp_mst_topology_mgr *mgr,
+                                           struct drm_connector *connector)
+{
+       struct radeon_connector *master = container_of(mgr, struct radeon_connector, mst_mgr);
+       struct drm_device *dev = master->base.dev;
+       struct radeon_device *rdev = dev->dev_private;
+
+       drm_connector_unregister(connector);
+       /* need to nuke the connector */
+       mutex_lock(&dev->mode_config.mutex);
+       /* dpms off */
+       radeon_fb_remove_connector(rdev, connector);
+
+       drm_connector_cleanup(connector);
+       mutex_unlock(&dev->mode_config.mutex);
+       drm_reinit_primary_mode_group(dev);
+
+
+       kfree(connector);
+       DRM_DEBUG_KMS("\n");
+}
+
+static void radeon_dp_mst_hotplug(struct drm_dp_mst_topology_mgr *mgr)
+{
+       struct radeon_connector *master = container_of(mgr, struct radeon_connector, mst_mgr);
+       struct drm_device *dev = master->base.dev;
+
+       drm_kms_helper_hotplug_event(dev);
+}
+
+struct drm_dp_mst_topology_cbs mst_cbs = {
+       .add_connector = radeon_dp_add_mst_connector,
+       .destroy_connector = radeon_dp_destroy_mst_connector,
+       .hotplug = radeon_dp_mst_hotplug,
+};
+
+struct radeon_connector *radeon_mst_find_connector(struct drm_encoder *encoder)
+{
+       struct drm_device *dev = encoder->dev;
+       struct drm_connector *connector;
+
+       list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+               struct radeon_connector *radeon_connector = to_radeon_connector(connector);
+               if (!connector->encoder)
+                       continue;
+               if (!radeon_connector->is_mst_connector)
+                       continue;
+
+               DRM_DEBUG_KMS("checking %p vs %p\n", connector->encoder, encoder);
+               if (connector->encoder == encoder)
+                       return radeon_connector;
+       }
+       return NULL;
+}
+
+void radeon_dp_mst_prepare_pll(struct drm_crtc *crtc, struct drm_display_mode *mode)
+{
+       struct radeon_crtc *radeon_crtc = to_radeon_crtc(crtc);
+       struct drm_device *dev = crtc->dev;
+       struct radeon_device *rdev = dev->dev_private;
+       struct radeon_encoder *radeon_encoder = to_radeon_encoder(radeon_crtc->encoder);
+       struct radeon_encoder_mst *mst_enc = radeon_encoder->enc_priv;
+       struct radeon_connector *radeon_connector = radeon_mst_find_connector(&radeon_encoder->base);
+       int dp_clock;
+       struct radeon_connector_atom_dig *dig_connector = mst_enc->connector->con_priv;
+
+       if (radeon_connector) {
+               radeon_connector->pixelclock_for_modeset = mode->clock;
+               if (radeon_connector->base.display_info.bpc)
+                       radeon_crtc->bpc = radeon_connector->base.display_info.bpc;
+               else
+                       radeon_crtc->bpc = 8;
+       }
+
+       DRM_DEBUG_KMS("dp_clock %p %d\n", dig_connector, dig_connector->dp_clock);
+       dp_clock = dig_connector->dp_clock;
+       radeon_crtc->ss_enabled =
+               radeon_atombios_get_asic_ss_info(rdev, &radeon_crtc->ss,
+                                                ASIC_INTERNAL_SS_ON_DP,
+                                                dp_clock);
+}
+
+static void
+radeon_mst_encoder_dpms(struct drm_encoder *encoder, int mode)
+{
+       struct drm_device *dev = encoder->dev;
+       struct radeon_device *rdev = dev->dev_private;
+       struct radeon_encoder *radeon_encoder, *primary;
+       struct radeon_encoder_mst *mst_enc;
+       struct radeon_encoder_atom_dig *dig_enc;
+       struct radeon_connector *radeon_connector;
+       struct drm_crtc *crtc;
+       struct radeon_crtc *radeon_crtc;
+       int ret, slots;
+
+       if (!ASIC_IS_DCE5(rdev)) {
+               DRM_ERROR("got mst dpms on non-DCE5\n");
+               return;
+       }
+
+       radeon_connector = radeon_mst_find_connector(encoder);
+       if (!radeon_connector)
+               return;
+
+       radeon_encoder = to_radeon_encoder(encoder);
+
+       mst_enc = radeon_encoder->enc_priv;
+
+       primary = mst_enc->primary;
+
+       dig_enc = primary->enc_priv;
+
+       crtc = encoder->crtc;
+       DRM_DEBUG_KMS("got connector %d\n", dig_enc->active_mst_links);
+
+       switch (mode) {
+       case DRM_MODE_DPMS_ON:
+               dig_enc->active_mst_links++;
+
+               radeon_crtc = to_radeon_crtc(crtc);
+
+               if (dig_enc->active_mst_links == 1) {
+                       mst_enc->fe = dig_enc->dig_encoder;
+                       mst_enc->fe_from_be = true;
+                       atombios_set_mst_encoder_crtc_source(encoder, mst_enc->fe);
+
+                       atombios_dig_encoder_setup(&primary->base, ATOM_ENCODER_CMD_SETUP, 0);
+                       atombios_dig_transmitter_setup2(&primary->base, ATOM_TRANSMITTER_ACTION_ENABLE,
+                                                       0, 0, dig_enc->dig_encoder);
+
+                       if (radeon_dp_needs_link_train(mst_enc->connector) ||
+                           dig_enc->active_mst_links == 1) {
+                               radeon_dp_link_train(&primary->base, &mst_enc->connector->base);
+                       }
+
+               } else {
+                       mst_enc->fe = radeon_atom_pick_dig_encoder(encoder, radeon_crtc->crtc_id);
+                       if (mst_enc->fe == -1)
+                               DRM_ERROR("failed to get frontend for dig encoder\n");
+                       mst_enc->fe_from_be = false;
+                       atombios_set_mst_encoder_crtc_source(encoder, mst_enc->fe);
+               }
+
+               DRM_DEBUG_KMS("dig encoder is %d %d %d\n", dig_enc->dig_encoder,
+                             dig_enc->linkb, radeon_crtc->crtc_id);
+
+               ret = drm_dp_mst_allocate_vcpi(&radeon_connector->mst_port->mst_mgr,
+                                              radeon_connector->port,
+                                              mst_enc->pbn, &slots);
+               ret = drm_dp_update_payload_part1(&radeon_connector->mst_port->mst_mgr);
+
+               radeon_dp_mst_set_be_cntl(primary, mst_enc,
+                                         radeon_connector->mst_port->hpd.hpd, true);
+
+               mst_enc->enc_active = true;
+               radeon_dp_mst_update_stream_attribs(radeon_connector->mst_port, primary);
+               radeon_dp_mst_set_vcp_size(radeon_encoder, slots, 0);
+
+               atombios_dig_encoder_setup2(&primary->base, ATOM_ENCODER_CMD_DP_VIDEO_ON, 0,
+                                           mst_enc->fe);
+               ret = drm_dp_check_act_status(&radeon_connector->mst_port->mst_mgr);
+
+               ret = drm_dp_update_payload_part2(&radeon_connector->mst_port->mst_mgr);
+
+               break;
+       case DRM_MODE_DPMS_STANDBY:
+       case DRM_MODE_DPMS_SUSPEND:
+       case DRM_MODE_DPMS_OFF:
+               DRM_ERROR("DPMS OFF %d\n", dig_enc->active_mst_links);
+
+               if (!mst_enc->enc_active)
+                       return;
+
+               drm_dp_mst_reset_vcpi_slots(&radeon_connector->mst_port->mst_mgr, mst_enc->port);
+               ret = drm_dp_update_payload_part1(&radeon_connector->mst_port->mst_mgr);
+
+               drm_dp_check_act_status(&radeon_connector->mst_port->mst_mgr);
+               /* and this can also fail */
+               drm_dp_update_payload_part2(&radeon_connector->mst_port->mst_mgr);
+
+               drm_dp_mst_deallocate_vcpi(&radeon_connector->mst_port->mst_mgr, mst_enc->port);
+
+               mst_enc->enc_active = false;
+               radeon_dp_mst_update_stream_attribs(radeon_connector->mst_port, primary);
+
+               radeon_dp_mst_set_be_cntl(primary, mst_enc,
+                                         radeon_connector->mst_port->hpd.hpd, false);
+               atombios_dig_encoder_setup2(&primary->base, ATOM_ENCODER_CMD_DP_VIDEO_OFF, 0,
+                                           mst_enc->fe);
+
+               if (!mst_enc->fe_from_be)
+                       radeon_atom_release_dig_encoder(rdev, mst_enc->fe);
+
+               mst_enc->fe_from_be = false;
+               dig_enc->active_mst_links--;
+               if (dig_enc->active_mst_links == 0) {
+                       /* drop link */
+               }
+
+               break;
+       }
+
+}
+
+static bool radeon_mst_mode_fixup(struct drm_encoder *encoder,
+                                  const struct drm_display_mode *mode,
+                                  struct drm_display_mode *adjusted_mode)
+{
+       struct radeon_encoder_mst *mst_enc;
+       struct radeon_encoder *radeon_encoder = to_radeon_encoder(encoder);
+       int bpp = 24;
+
+       mst_enc = radeon_encoder->enc_priv;
+
+       mst_enc->pbn = drm_dp_calc_pbn_mode(adjusted_mode->clock, bpp);
+
+       mst_enc->primary->active_device = mst_enc->primary->devices & mst_enc->connector->devices;
+       DRM_DEBUG_KMS("setting active device to %08x from %08x %08x for encoder %d\n",
+                     mst_enc->primary->active_device, mst_enc->primary->devices,
+                     mst_enc->connector->devices, mst_enc->primary->base.encoder_type);
+
+
+       drm_mode_set_crtcinfo(adjusted_mode, 0);
+       {
+         struct radeon_connector_atom_dig *dig_connector;
+
+         dig_connector = mst_enc->connector->con_priv;
+         dig_connector->dp_lane_count = drm_dp_max_lane_count(dig_connector->dpcd);
+         dig_connector->dp_clock = radeon_dp_get_max_link_rate(&mst_enc->connector->base,
+                                                               dig_connector->dpcd);
+         DRM_DEBUG_KMS("dig clock %p %d %d\n", dig_connector,
+                       dig_connector->dp_lane_count, dig_connector->dp_clock);
+       }
+       return true;
+}
+
+static void radeon_mst_encoder_prepare(struct drm_encoder *encoder)
+{
+       struct radeon_connector *radeon_connector;
+       struct radeon_encoder *radeon_encoder, *primary;
+       struct radeon_encoder_mst *mst_enc;
+       struct radeon_encoder_atom_dig *dig_enc;
+
+       radeon_connector = radeon_mst_find_connector(encoder);
+       if (!radeon_connector) {
+               DRM_DEBUG_KMS("failed to find connector %p\n", encoder);
+               return;
+       }
+       radeon_encoder = to_radeon_encoder(encoder);
+
+       radeon_mst_encoder_dpms(encoder, DRM_MODE_DPMS_OFF);
+
+       mst_enc = radeon_encoder->enc_priv;
+
+       primary = mst_enc->primary;
+
+       dig_enc = primary->enc_priv;
+
+       mst_enc->port = radeon_connector->port;
+
+       if (dig_enc->dig_encoder == -1) {
+               dig_enc->dig_encoder = radeon_atom_pick_dig_encoder(&primary->base, -1);
+               primary->offset = radeon_atom_set_enc_offset(dig_enc->dig_encoder);
+               atombios_set_mst_encoder_crtc_source(encoder, dig_enc->dig_encoder);
+
+
+       }
+       DRM_DEBUG_KMS("%d %d\n", dig_enc->dig_encoder, primary->offset);
+}
+
+static void
+radeon_mst_encoder_mode_set(struct drm_encoder *encoder,
+                            struct drm_display_mode *mode,
+                            struct drm_display_mode *adjusted_mode)
+{
+       DRM_DEBUG_KMS("\n");
+}
+
+static void radeon_mst_encoder_commit(struct drm_encoder *encoder)
+{
+       radeon_mst_encoder_dpms(encoder, DRM_MODE_DPMS_ON);
+       DRM_DEBUG_KMS("\n");
+}
+
+static const struct drm_encoder_helper_funcs radeon_mst_helper_funcs = {
+       .dpms = radeon_mst_encoder_dpms,
+       .mode_fixup = radeon_mst_mode_fixup,
+       .prepare = radeon_mst_encoder_prepare,
+       .mode_set = radeon_mst_encoder_mode_set,
+       .commit = radeon_mst_encoder_commit,
+};
+
+void radeon_dp_mst_encoder_destroy(struct drm_encoder *encoder)
+{
+       drm_encoder_cleanup(encoder);
+       kfree(encoder);
+}
+
+static const struct drm_encoder_funcs radeon_dp_mst_enc_funcs = {
+       .destroy = radeon_dp_mst_encoder_destroy,
+};
+
+static struct radeon_encoder *
+radeon_dp_create_fake_mst_encoder(struct radeon_connector *connector)
+{
+       struct drm_device *dev = connector->base.dev;
+       struct radeon_device *rdev = dev->dev_private;
+       struct radeon_encoder *radeon_encoder;
+       struct radeon_encoder_mst *mst_enc;
+       struct drm_encoder *encoder;
+       struct drm_connector_helper_funcs *connector_funcs = connector->base.helper_private;
+       struct drm_encoder *enc_master = connector_funcs->best_encoder(&connector->base);
+
+       DRM_DEBUG_KMS("enc master is %p\n", enc_master);
+       radeon_encoder = kzalloc(sizeof(*radeon_encoder), GFP_KERNEL);
+       if (!radeon_encoder)
+               return NULL;
+
+       radeon_encoder->enc_priv = kzalloc(sizeof(*mst_enc), GFP_KERNEL);
+       if (!radeon_encoder->enc_priv) {
+               kfree(radeon_encoder);
+               return NULL;
+       }
+       encoder = &radeon_encoder->base;
+       switch (rdev->num_crtc) {
+       case 1:
+               encoder->possible_crtcs = 0x1;
+               break;
+       case 2:
+       default:
+               encoder->possible_crtcs = 0x3;
+               break;
+       case 4:
+               encoder->possible_crtcs = 0xf;
+               break;
+       case 6:
+               encoder->possible_crtcs = 0x3f;
+               break;
+       }
+
+       drm_encoder_init(dev, &radeon_encoder->base, &radeon_dp_mst_enc_funcs,
+                        DRM_MODE_ENCODER_DPMST);
+       drm_encoder_helper_add(encoder, &radeon_mst_helper_funcs);
+
+       mst_enc = radeon_encoder->enc_priv;
+       mst_enc->connector = connector;
+       mst_enc->primary = to_radeon_encoder(enc_master);
+       radeon_encoder->is_mst_encoder = true;
+       return radeon_encoder;
+}
+
+int
+radeon_dp_mst_init(struct radeon_connector *radeon_connector)
+{
+       struct drm_device *dev = radeon_connector->base.dev;
+
+       if (!radeon_connector->ddc_bus->has_aux)
+               return 0;
+
+       radeon_connector->mst_mgr.cbs = &mst_cbs;
+       return drm_dp_mst_topology_mgr_init(&radeon_connector->mst_mgr, dev->dev,
+                                           &radeon_connector->ddc_bus->aux, 16, 6,
+                                           radeon_connector->base.base.id);
+}
+
+int
+radeon_dp_mst_probe(struct radeon_connector *radeon_connector)
+{
+       struct radeon_connector_atom_dig *dig_connector = radeon_connector->con_priv;
+       int ret;
+       u8 msg[1];
+
+       if (dig_connector->dpcd[DP_DPCD_REV] < 0x12)
+               return 0;
+
+       ret = drm_dp_dpcd_read(&radeon_connector->ddc_bus->aux, DP_MSTM_CAP, msg,
+                              1);
+       if (ret) {
+               if (msg[0] & DP_MST_CAP) {
+                       DRM_DEBUG_KMS("Sink is MST capable\n");
+                       dig_connector->is_mst = true;
+               } else {
+                       DRM_DEBUG_KMS("Sink is not MST capable\n");
+                       dig_connector->is_mst = false;
+               }
+
+       }
+       drm_dp_mst_topology_mgr_set_mst(&radeon_connector->mst_mgr,
+                                       dig_connector->is_mst);
+       return dig_connector->is_mst;
+}
+
+int
+radeon_dp_mst_check_status(struct radeon_connector *radeon_connector)
+{
+       struct radeon_connector_atom_dig *dig_connector = radeon_connector->con_priv;
+       int retry;
+
+       if (dig_connector->is_mst) {
+               u8 esi[16] = { 0 };
+               int dret;
+               int ret = 0;
+               bool handled;
+
+               dret = drm_dp_dpcd_read(&radeon_connector->ddc_bus->aux,
+                                      DP_SINK_COUNT_ESI, esi, 8);
+go_again:
+               if (dret == 8) {
+                       DRM_DEBUG_KMS("got esi %02x %02x %02x\n", esi[0], esi[1], esi[2]);
+                       ret = drm_dp_mst_hpd_irq(&radeon_connector->mst_mgr, esi, &handled);
+
+                       if (handled) {
+                               for (retry = 0; retry < 3; retry++) {
+                                       int wret;
+                                       wret = drm_dp_dpcd_write(&radeon_connector->ddc_bus->aux,
+                                                                DP_SINK_COUNT_ESI + 1, &esi[1], 3);
+                                       if (wret == 3)
+                                               break;
+                               }
+
+                               dret = drm_dp_dpcd_read(&radeon_connector->ddc_bus->aux,
+                                                       DP_SINK_COUNT_ESI, esi, 8);
+                               if (dret == 8) {
+                                       DRM_DEBUG_KMS("got esi2 %02x %02x %02x\n", esi[0], esi[1], esi[2]);
+                                       goto go_again;
+                               }
+                       } else
+                               ret = 0;
+
+                       return ret;
+               } else {
+                       DRM_DEBUG_KMS("failed to get ESI - device may have failed %d\n", ret);
+                       dig_connector->is_mst = false;
+                       drm_dp_mst_topology_mgr_set_mst(&radeon_connector->mst_mgr,
+                                                       dig_connector->is_mst);
+                       /* send a hotplug event */
+               }
+       }
+       return -EINVAL;
+}
+
+#if defined(CONFIG_DEBUG_FS)
+
+static int radeon_debugfs_mst_info(struct seq_file *m, void *data)
+{
+       struct drm_info_node *node = (struct drm_info_node *)m->private;
+       struct drm_device *dev = node->minor->dev;
+       struct drm_connector *connector;
+       struct radeon_connector *radeon_connector;
+       struct radeon_connector_atom_dig *dig_connector;
+       int i;
+
+       drm_modeset_lock_all(dev);
+       list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+               if (connector->connector_type != DRM_MODE_CONNECTOR_DisplayPort)
+                       continue;
+
+               radeon_connector = to_radeon_connector(connector);
+               dig_connector = radeon_connector->con_priv;
+               if (radeon_connector->is_mst_connector)
+                       continue;
+               if (!dig_connector->is_mst)
+                       continue;
+               drm_dp_mst_dump_topology(m, &radeon_connector->mst_mgr);
+
+               for (i = 0; i < radeon_connector->enabled_attribs; i++)
+                       seq_printf(m, "attrib %d: %d %d\n", i,
+                                  radeon_connector->cur_stream_attribs[i].fe,
+                                  radeon_connector->cur_stream_attribs[i].slots);
+       }
+       drm_modeset_unlock_all(dev);
+       return 0;
+}
+
+static struct drm_info_list radeon_debugfs_mst_list[] = {
+       {"radeon_mst_info", &radeon_debugfs_mst_info, 0, NULL},
+};
+#endif
+
+int radeon_mst_debugfs_init(struct radeon_device *rdev)
+{
+#if defined(CONFIG_DEBUG_FS)
+       return radeon_debugfs_add_files(rdev, radeon_debugfs_mst_list, 1);
+#endif
+       return 0;
+}