diff options
| author | Wayne Lin <Wayne.Lin@amd.com> | 2022-04-20 10:32:15 +0800 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2022-06-06 14:43:18 -0400 |
| commit | 453b0016a054df0f442fda8a145b97a33816cab9 (patch) | |
| tree | b5b4b7094d8a05d12f14e6fa4baee4e302dd07d8 /drivers/gpu | |
| parent | 84de5c2e92dccb2bcfd5ff68af44960b808fe6bb (diff) | |
drm/amd/display: Detect dpcd_rev when hotplug mst monitor
[Why]
Once mst topology is constructed, later on new connected monitors
are reported to source by CSN message. Within CSN, there is no
carried info of DPCD_REV comparing to LINK_ADDRESS reply. As the
result, we might leave some ports connected to DP but without DPCD
revision number which will affect us determining the capability of
the DP Rx.
[How]
Send out remote DPCD read when the port's dpcd_rev is 0x0 in
detect_ctx(). Firstly, read out the value from DPCD 0x2200. If the
return value is 0x0, it's likely the DP1.2 DP Rx then we reques
revision from DPCD 0x0 again.
Reviewed-by: Hersen Wu <hersenwu@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c index 9221b6690a4a..a6d551ff89d1 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c @@ -344,12 +344,48 @@ dm_dp_mst_detect(struct drm_connector *connector, { struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector); struct amdgpu_dm_connector *master = aconnector->mst_port; + struct drm_dp_mst_port *port = aconnector->port; + int connection_status; if (drm_connector_is_unregistered(connector)) return connector_status_disconnected; - return drm_dp_mst_detect_port(connector, ctx, &master->mst_mgr, + connection_status = drm_dp_mst_detect_port(connector, ctx, &master->mst_mgr, aconnector->port); + + if (port->pdt != DP_PEER_DEVICE_NONE && !port->dpcd_rev) { + uint8_t dpcd_rev; + int ret; + + ret = drm_dp_dpcd_readb(&port->aux, DP_DP13_DPCD_REV, &dpcd_rev); + + if (ret == 1) { + port->dpcd_rev = dpcd_rev; + + /* Could be DP1.2 DP Rx case*/ + if (!dpcd_rev) { + ret = drm_dp_dpcd_readb(&port->aux, DP_DPCD_REV, &dpcd_rev); + + if (ret == 1) + port->dpcd_rev = dpcd_rev; + } + + if (!dpcd_rev) + DRM_DEBUG_KMS("Can't decide DPCD revision number!"); + } + + /* + * Could be legacy sink, logical port etc on DP1.2. + * Will get Nack under these cases when issue remote + * DPCD read. + */ + if (ret != 1) + DRM_DEBUG_KMS("Can't access DPCD"); + } else if (port->pdt == DP_PEER_DEVICE_NONE) { + port->dpcd_rev = 0; + } + + return connection_status; } static int dm_dp_mst_atomic_check(struct drm_connector *connector, |