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drm/dp_mst: Don't report ports connected if nothing is attached to them

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commit 873e5bb9fbd99e4a26c448b5c7af942a6d7aa60d upstream.

Reporting a port as connected if nothing is attached to them leads to
any i2c transactions on this port trying to use an uninitialized i2c
adapter, fix this.

Let's account for this case even if branch devices have no good reason
to report a port as plugged with their peer device type set to 'none'.

Fixes: db1a07956968 ("drm/dp_mst: Handle SST-only branch device case")
References: https://gitlab.freedesktop.org/drm/intel/-/issues/2987
References: https://gitlab.freedesktop.org/drm/intel/-/issues/1963
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: <stable@vger.kernel.org> # v5.5+
Cc: intel-gfx@lists.freedesktop.org
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Reported-by: Thiago Macieira <gitlab@gitlab.freedesktop.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210201120145.350258-1-imre.deak@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Imre Deak 2021-02-01 14:01:42 +02:00 committed by Greg Kroah-Hartman
parent 5a36371f8b
commit deae1e6365
1 changed files with 1 additions and 0 deletions
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1
drivers/gpu/drm/drm_dp_mst_topology.c
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@ -4224,6 +4224,7 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
switch (port->pdt) {
case DP_PEER_DEVICE_NONE:
break;
case DP_PEER_DEVICE_MST_BRANCHING:
if (!port->mcs)
ret = connector_status_connected;