[PATCH 1/4] drm/dp_mst: Don't report ports connected if nothing is attached to them

[Lyude Paul]

For the whole series:

Reviewed-by: Lyude Paul <lyude at redhat.com>

On Mon, 2021-02-01 at 14:01 +0200, Imre Deak wrote:
> 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 unplugged 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 at amd.com>
> Cc: Lyude Paul <lyude at redhat.com>
> Cc: <stable at vger.kernel.org> # v5.5+
> Cc: intel-gfx at lists.freedesktop.org
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/drm_dp_mst_topology.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c
> b/drivers/gpu/drm/drm_dp_mst_topology.c
> index e82b596d646c..deb7995f42fa 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -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;

-- 
Sincerely,
   Lyude Paul (she/her)
   Software Engineer at Red Hat
   
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