This is a note to let you know that I've just added the patch titled drm/dp_mst: Don't report ports connected if nothing is attached to them to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-dp_mst-don-t-report-ports-connected-if-nothing-is-attached-to-them.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 873e5bb9fbd99e4a26c448b5c7af942a6d7aa60d Mon Sep 17 00:00:00 2001 From: Imre Deak <imre.deak@xxxxxxxxx> Date: Mon, 1 Feb 2021 14:01:42 +0200 Subject: drm/dp_mst: Don't report ports connected if nothing is attached to them From: Imre Deak <imre.deak@xxxxxxxxx> 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@xxxxxxx> Cc: Lyude Paul <lyude@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> # v5.5+ Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx> Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx> Reported-by: Thiago Macieira <gitlab@xxxxxxxxxxxxxxxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20210201120145.350258-1-imre.deak@xxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/drm_dp_mst_topology.c | 1 + 1 file changed, 1 insertion(+) --- 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_connec switch (port->pdt) { case DP_PEER_DEVICE_NONE: + break; case DP_PEER_DEVICE_MST_BRANCHING: if (!port->mcs) ret = connector_status_connected; Patches currently in stable-queue which might be from imre.deak@xxxxxxxxx are queue-5.10/drm-dp_mst-don-t-report-ports-connected-if-nothing-is-attached-to-them.patch queue-5.10/drm-i915-tgl-make-sure-typec-fia-is-powered-up-when-initializing-it.patch