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drm/dp_mst: Don't forget to update port->input in drm_dp_mst_handle_conn_stat() 

This probably hasn't caused any problems up until now since it's
probably nearly impossible to encounter this in the wild, however if we
were to receive a connection status notification from the MST hub after
resume while we're in the middle of reprobing the link addresses for a
topology then there's a much larger chance that a port could have
changed from being an output port to input port (or vice versa). If we
forget to update this bit of information, we'll potentially ignore a
valid PDT change on a downstream port because we think it's an input
port.

So, make sure we read the input_port field in connection status
notifications in drm_dp_mst_handle_conn_stat() to prevent this from
happening once we've implemented suspend/resume reprobing.

Cc: Juston Li <juston.li@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Harry Wentland <hwentlan@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Sean Paul <sean@poorly.run>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191022023641.8026-8-lyude@redhat.com
This commit is contained in:
Lyude Paul 2019-10-16 17:50:15 -04:00
parent 3f9b3f02dd
commit dad7d84f88
1 changed files with 36 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

50
drivers/gpu/drm/drm_dp_mst_topology.c
View File

@ -2079,18 +2079,38 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
{
struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
struct drm_dp_mst_port *port;
int old_ddps;
bool dowork = false;
int old_ddps, ret;
u8 new_pdt;
bool dowork = false, create_connector = false;
port = drm_dp_get_port(mstb, conn_stat->port_number);
if (!port)
return;
/* Locking is only needed if the port's exposed to userspace */
if (port->connector)
if (port->connector) {
if (!port->input && conn_stat->input_port) {
/*
* We can't remove a connector from an already exposed
* port, so just throw the port out and make sure we
* reprobe the link address of it's parent MSTB
*/
drm_dp_mst_topology_unlink_port(mgr, port);
mstb->link_address_sent = false;
dowork = true;
goto out;
}
/* Locking is only needed if the port's exposed to userspace */
drm_modeset_lock(&mgr->base.lock, NULL);
} else if (port->input && !conn_stat->input_port) {
create_connector = true;
/* Reprobe link address so we get num_sdp_streams */
mstb->link_address_sent = false;
dowork = true;
}
old_ddps = port->ddps;
port->input = conn_stat->input_port;
port->mcs = conn_stat->message_capability_status;
port->ldps = conn_stat->legacy_device_plug_status;
port->ddps = conn_stat->displayport_device_plug_status;
@ -2103,21 +2123,23 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
}
}
if (!port->input) {
int ret = drm_dp_port_set_pdt(port,
conn_stat->peer_device_type);
if (ret == 1) {
dowork = true;
} else if (ret < 0) {
DRM_ERROR("Failed to change PDT for port %p: %d\n",
port, ret);
dowork = false;
}
new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;
ret = drm_dp_port_set_pdt(port, new_pdt);
if (ret == 1) {
dowork = true;
} else if (ret < 0) {
DRM_ERROR("Failed to change PDT for port %p: %d\n",
port, ret);
dowork = false;
}
if (port->connector)
drm_modeset_unlock(&mgr->base.lock);
else if (create_connector)
drm_dp_mst_port_add_connector(mstb, port);
out:
drm_dp_mst_topology_put_port(port);
if (dowork)
queue_work(system_long_wq, &mstb->mgr->work);