6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Wayne Lin <Wayne.Lin@xxxxxxx> commit b5cd418f016fb801be413fd52fe4711d2d13018c upstream. [Why & How] Currently in dm_dp_mst_is_port_support_mode(), when valdidating mode under dsc decoding at the last DP link config, we only validate the case when there is an UFP. However, if the MSTB LCT=1, there is no UFP. Under this case, use root_link_bw_in_kbps as the available bw to compare. Link: https://gitlab.freedesktop.org/drm/amd/-/issues/3720 Fixes: fa57924c76d9 ("drm/amd/display: Refactor function dm_dp_mst_is_port_support_mode()") Cc: Mario Limonciello <mario.limonciello@xxxxxxx> Cc: Alex Deucher <alexander.deucher@xxxxxxx> Reviewed-by: Jerry Zuo <jerry.zuo@xxxxxxx> Signed-off-by: Wayne Lin <Wayne.Lin@xxxxxxx> Signed-off-by: Tom Chung <chiahsuan.chung@xxxxxxx> Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> (cherry picked from commit a04d9534a8a75b2806c5321c387be450c364b55e) Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 14 +++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c @@ -1831,11 +1831,15 @@ enum dc_status dm_dp_mst_is_port_support if (immediate_upstream_port) { virtual_channel_bw_in_kbps = kbps_from_pbn(immediate_upstream_port->full_pbn); virtual_channel_bw_in_kbps = min(root_link_bw_in_kbps, virtual_channel_bw_in_kbps); - if (bw_range.min_kbps > virtual_channel_bw_in_kbps) { - DRM_DEBUG_DRIVER("MST_DSC dsc decode at last link." - "Max dsc compression can't fit into MST available bw\n"); - return DC_FAIL_BANDWIDTH_VALIDATE; - } + } else { + /* For topology LCT 1 case - only one mstb*/ + virtual_channel_bw_in_kbps = root_link_bw_in_kbps; + } + + if (bw_range.min_kbps > virtual_channel_bw_in_kbps) { + DRM_DEBUG_DRIVER("MST_DSC dsc decode at last link." + "Max dsc compression can't fit into MST available bw\n"); + return DC_FAIL_BANDWIDTH_VALIDATE; } }
