4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Andrey Grodzovsky <[email protected]> commit c175cd16df272119534058f28cbd5eeac6ff2d24 upstream. On DELL U3014 if you clear the table before enabling MST it sometimes hangs the receiver. Signed-off-by: Andrey Grodzovsky <[email protected]> Reviewed-by: Harry Wentland <[email protected]> Acked-by: Alex Deucher <[email protected]> Signed-off-by: Dave Airlie <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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;
