FAILED: patch "[PATCH] drm/display/dp_mst: Fix down/up message handling after sink" failed to apply to 4.14-stable tree

The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.14.y
git checkout FETCH_HEAD
git cherry-pick -x 1d082618bbf3b6755b8cc68c0a8122af2842d593
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '[email protected]' --subject-prefix 'PATCH 4.14.y' HEAD^..

Possible dependencies:

1d082618bbf3 ("drm/display/dp_mst: Fix down/up message handling after sink disconnect") da68386d9edb ("drm: Rename dp/ to display/")
6c64ae228f08 ("Backmerge tag 'v5.17-rc6' into drm-next")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 1d082618bbf3b6755b8cc68c0a8122af2842d593 Mon Sep 17 00:00:00 2001
From: Imre Deak <[email protected]>
Date: Wed, 14 Dec 2022 20:42:56 +0200
Subject: [PATCH] drm/display/dp_mst: Fix down/up message handling after sink
disconnect

If the sink gets disconnected during receiving a multi-packet DP MST AUX down-reply/up-request sideband message, the state keeping track of which packets have been received already is not reset. This results in a failed sanity check for the subsequent message packet received after a sink is reconnected (due to the pending message not yet completed with an end-of-message-transfer packet), indicated by the

"sideband msg set header failed"

error.

Fix the above by resetting the up/down message reception state after a disconnect event.

index 51a46689cda7..90819fff2c9b 100644
@@ -3641,6 +3641,9 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
 		drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
 		ret = 0;
 		mgr->payload_id_table_cleared = false;
+
+		memset(&mgr->down_rep_recv, 0, sizeof(mgr->down_rep_recv));
+		memset(&mgr->up_req_recv, 0, sizeof(mgr->up_req_recv));
 	}
 
 out_unlock: