Now that we've fixed the issue with using the incorrect topology manager, we're actually grabbing the topology manager's lock - and consequently deadlocking. Luckily for us though, there's actually nothing in AMD's DSC state computation code that really should need this lock. The one exception is the mutex_lock() in dm_dp_mst_is_port_support_mode(), however we grab no locks beneath &mgr->lock there so that should be fine to leave be.

Signed-off-by: Lyude Paul lyude@redhat.com Gitlab issue: https://gitlab.freedesktop.org/drm/amd/-/issues/2171 Fixes: 8c20a1ed9b4f ("drm/amd/display: MST DSC compute fair share") Cc: stable@vger.kernel.org # v5.6+ --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 4 ---- 1 file changed, 4 deletions(-)

diff --git 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 index 5196c9a0e432d..59648f5ffb59d 100644 --- 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 @@ -1148,10 +1148,8 @@ int compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, continue;

mst_mgr = aconnector->port->mgr; - mutex_lock(&mst_mgr->lock); ret = compute_mst_dsc_configs_for_link(state, dc_state, stream->link, vars, mst_mgr, &link_vars_start_index); - mutex_unlock(&mst_mgr->lock); if (ret != 0) return ret;

@@ -1208,10 +1206,8 @@ static int pre_compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, continue;

mst_mgr = aconnector->port->mgr; - mutex_lock(&mst_mgr->lock); ret = compute_mst_dsc_configs_for_link(state, dc_state, stream->link, vars, mst_mgr, &link_vars_start_index); - mutex_unlock(&mst_mgr->lock); if (ret != 0) return ret;