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[4.2.y-ckt,stable] Patch "drm/dp/mst: Reverse order of MST enable and clearing VC payload table." has been added to the 4.2.y-ckt tree

Message ID 1457389968-29084-1-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa March 7, 2016, 10:32 p.m. UTC 
This is a note to let you know that I have just added a patch titled

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

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt5.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

From 679b485bbcb991ce51ad1fb733621a2007c3a413 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.

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: Kamal Mostafa <kamal@canonical.com>
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--
2.7.0
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Patch

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 0ec9ad5..2c691b3 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1969,6 +1969,12 @@  int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
 		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;
@@ -1976,12 +1982,6 @@  int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
 			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;
-		}
-

 		/* sort out guid */
 		ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, mgr->guid, 16);