Patch "drm/dp/mst: Reverse order of MST enable and clearing VC payload table." has been added to the 4.4-stable tree

Patch "drm/dp/mst: Reverse order of MST enable and clearing VC payload table." has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    drm/dp/mst: Reverse order of MST enable and clearing VC payload table.

to the 4.4-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-reverse-order-of-mst-enable-and-clearing-vc-payload-table.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From c175cd16df272119534058f28cbd5eeac6ff2d24 Mon Sep 17 00:00:00 2001
From: Andrey Grodzovsky <Andrey.Grodzovsky@amd.com>
Date: Fri, 22 Jan 2016 17:07:29 -0500
Subject: drm/dp/mst: Reverse order of MST enable and clearing VC payload table.

From: Andrey Grodzovsky <Andrey.Grodzovsky@amd.com>

commit c175cd16df272119534058f28cbd5eeac6ff2d24 upstream.

On DELL U3014 if you clear the table before enabling MST it sometimes
hangs the receiver.

Signed-off-by: Andrey Grodzovsky <Andrey.Grodzovsky@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/drm_dp_mst_topology.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1976,6 +1976,12 @@ int drm_dp_mst_topology_mgr_set_mst(stru
 		mgr->mst_primary = mstb;
 		kref_get(&mgr->mst_primary->kref);
 
+		ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
+							 DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
+		if (ret < 0) {
+			goto out_unlock;
+		}
+
 		{
 			struct drm_dp_payload reset_pay;
 			reset_pay.start_slot = 0;
@@ -1983,12 +1989,6 @@ int drm_dp_mst_topology_mgr_set_mst(stru
 			drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
 		}
 
-		ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
-					 DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
-		if (ret < 0) {
-			goto out_unlock;
-		}
-
 		queue_work(system_long_wq, &mgr->work);
 
 		ret = 0;


Patches currently in stable-queue which might be from Andrey.Grodzovsky@amd.com are

queue-4.4/drm-dp-mst-reverse-order-of-mst-enable-and-clearing-vc-payload-table.patch