diff options
Diffstat (limited to 'drivers/gpu/drm/drm_dp_mst_topology.c')
| -rw-r--r-- | drivers/gpu/drm/drm_dp_mst_topology.c | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index b273d9ba7cbf..54864400015d 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -3637,6 +3637,28 @@ static int drm_dp_get_vc_payload_bw(u8 dp_link_bw, u8 dp_link_count) } /** + * drm_dp_read_mst_cap() - check whether or not a sink supports MST + * @aux: The DP AUX channel to use + * @dpcd: A cached copy of the DPCD capabilities for this sink + * + * Returns: %True if the sink supports MST, %false otherwise + */ +bool drm_dp_read_mst_cap(struct drm_dp_aux *aux, + const u8 dpcd[DP_RECEIVER_CAP_SIZE]) +{ + u8 mstm_cap; + + if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12) + return false; + + if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, &mstm_cap) != 1) + return false; + + return mstm_cap & DP_MST_CAP; +} +EXPORT_SYMBOL(drm_dp_read_mst_cap); + +/** * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager * @mgr: manager to set state for * @mst_state: true to enable MST on this connector - false to disable. @@ -5190,8 +5212,8 @@ int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm crtc = conn_state->crtc; - if (WARN_ON(!crtc)) - return -EINVAL; + if (!crtc) + continue; if (!drm_dp_mst_dsc_aux_for_port(pos->port)) continue; |