As of DP1.4, ENUM_PATH_RESOURCES returns a bit indicating if FEC can be supported up to that point in the MST network.
The bit is the first byte of the ENUM_PATH_RESOURCES ack reply, bottom-most bit (refer to section 2.11.9.4 of DP standard, v1.4)
That value is needed for FEC and DSC support
Store it on drm_dp_mst_port
Signed-off-by: David Francis David.Francis@amd.com --- drivers/gpu/drm/drm_dp_mst_topology.c | 2 ++ include/drm/drm_dp_mst_helper.h | 3 +++ 2 files changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 398e7314ea8b..53a0ad16e37b 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -552,6 +552,7 @@ static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband { int idx = 1; repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf; + repmsg->u.path_resources.fec_capable = raw->msg[idx] & 0x1; idx++; if (idx > raw->curlen) goto fail_len; @@ -2180,6 +2181,7 @@ static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr, DRM_DEBUG_KMS("enum path resources %d: %d %d\n", txmsg->reply.u.path_resources.port_number, txmsg->reply.u.path_resources.full_payload_bw_number, txmsg->reply.u.path_resources.avail_payload_bw_number); port->available_pbn = txmsg->reply.u.path_resources.avail_payload_bw_number; + port->fec_capable = txmsg->reply.u.path_resources.fec_capable; } }
diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h index 2ba6253ea6d3..e1801781fff5 100644 --- a/include/drm/drm_dp_mst_helper.h +++ b/include/drm/drm_dp_mst_helper.h @@ -108,6 +108,8 @@ struct drm_dp_mst_port { * audio-capable. */ bool has_audio; + + bool fec_capable; };
/** @@ -312,6 +314,7 @@ struct drm_dp_port_number_req {
struct drm_dp_enum_path_resources_ack_reply { u8 port_number; + bool fec_capable; u16 full_payload_bw_number; u16 avail_payload_bw_number; };