[4.2.y-ckt stable] Patch "drm/dp/mst: fix in MSTB RAD initialization" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    drm/dp/mst: fix in MSTB RAD initialization

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-ckt3.

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 8ad43a0168a794839a1dd6a3771796b16f198340 Mon Sep 17 00:00:00 2001
From: Mykola Lysenko <Mykola.Lysenko at amd.com>
Date: Fri, 25 Dec 2015 16:14:47 +0800
Subject: drm/dp/mst: fix in MSTB RAD initialization

commit 75af4c8c4c0f60d7ad135419805798f144e9baf9 upstream.

This fix is needed to support more then two
branch displays, so RAD address consist at
least of 2 elements

Acked-by: Dave Airlie <airlied at gmail.com>
Signed-off-by: Mykola Lysenko <Mykola.Lysenko at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index d620fe9..74c0c08 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -973,17 +973,17 @@ static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u
 static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
 				 u8 *rad)
 {
-	int lct = port->parent->lct;
+	int parent_lct = port->parent->lct;
 	int shift = 4;
-	int idx = lct / 2;
-	if (lct > 1) {
-		memcpy(rad, port->parent->rad, idx);
-		shift = (lct % 2) ? 4 : 0;
+	int idx = (parent_lct - 1) / 2;
+	if (parent_lct > 1) {
+		memcpy(rad, port->parent->rad, idx + 1);
+		shift = (parent_lct % 2) ? 4 : 0;
 	} else
 		rad[0] = 0;

 	rad[idx] |= port->port_num << shift;
-	return lct + 1;
+	return parent_lct + 1;
 }

 /*
--
1.9.1