From: Wayne Lin wayne.lin@amd.com

link_rate sometime will be changed when DP MST connector hotplug, so pbn_div also need be updated; otherwise, it will mismatch with link_rate, causes no output in external monitor.

This is a backport of commit 9cdef4f72037 ("drm/amd/display: pbn_div need be updated for hotplug event") to 6.1. This fixes a display light up failure on some docking stations.

Cc: stable@vger.kernel.org Tested-by: Daniel Wheeler daniel.wheeler@amd.com Reviewed-by: Jerry Zuo jerry.zuo@amd.com Acked-by: Rodrigo Siqueira rodrigo.siqueira@amd.com Signed-off-by: Wade Wang wade.wang@hp.com Signed-off-by: Wayne Lin wayne.lin@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com (cherry picked from commit 9cdef4f720376ef0fb0febce1ed2377c19e531f9) --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)

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 13e0b521e3db..f02e509d5fac 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -6677,8 +6677,7 @@ static int dm_encoder_helper_atomic_check(struct drm_encoder *encoder, if (IS_ERR(mst_state)) return PTR_ERR(mst_state);

- if (!mst_state->pbn_div) - mst_state->pbn_div = dm_mst_get_pbn_divider(aconnector->mst_port->dc_link); + mst_state->pbn_div = dm_mst_get_pbn_divider(aconnector->mst_port->dc_link);

if (!state->duplicated) { int max_bpc = conn_state->max_requested_bpc;