From: Andrey Grodzovsky <Andrey.Grodzovsky@xxxxxxx>
This patch has been added to the 4.1 stable tree. If you have any
objections, please let us know.
===============
[ Upstream commit c175cd16df272119534058f28cbd5eeac6ff2d24 ]
On DELL U3014 if you clear the table before enabling MST it sometimes
hangs the receiver.
Signed-off-by: Andrey Grodzovsky <Andrey.Grodzovsky@xxxxxxx>
Reviewed-by: Harry Wentland <harry.wentland@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Acked-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
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 a2eb7e5..a4fbf02 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1974,6 +1974,12 @@ 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;
@@ -1981,12 +1987,6 @@ 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;
- }
-
queue_work(system_long_wq, &mgr->work);
ret = 0;
--
2.5.0
--
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