From: Wayne Lin wayne.lin@amd.com

[Why] Like commit ec5fa9fcdeca ("drm/amd/display: Adjust the MST resume flow"), we want to avoid handling mst topology changes before restoring the old state. If we enable DP_UP_REQ_EN before calling drm_atomic_helper_resume(), have changce to handle CSN event first and fire hotplug event before restoring the cached state.

[How] Disable mst branch sending up request event before we restoring the cached state. DP_UP_REQ_EN will be set later when we call drm_dp_mst_topology_mgr_resume().

Cc: Mario Limonciello mario.limonciello@amd.com Cc: Alex Deucher alexander.deucher@amd.com Cc: stable@vger.kernel.org

Reviewed-by: Hersen Wu hersenxs.wu@amd.com Signed-off-by: Wayne Lin wayne.lin@amd.com --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 1 - 1 file changed, 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 9d36dba914e9..961b5984afa0 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -2429,7 +2429,6 @@ static void resume_mst_branch_status(struct drm_dp_mst_topology_mgr *mgr)

ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, DP_MST_EN | - DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC); if (ret < 0) { drm_dbg_kms(mgr->dev, "mst write failed - undocked during suspend?\n");