On 08/04, Wayne Lin wrote: > [Why] > Under DP daisy chain scenario as below: > > Src - Monitor_1 - Monitor_2 > > If unplug 2nd Monitor_2 and plug in again, observe that Monitor_1 > doesn't light up. > > When unplug 2nd monitor, we clear the > dc_link->cur_link_settings.lane_count in dm_dp_destroy_mst_connector(). > However this link status is a shared data structure by all connected mst > monitors. Although the 2nd monitor is gone, this link status should > still be retained for other connected mst monitors. Otherwise, when we > plug the 2nd monitor in again, we find out that main link is not trained > and do link training again. Payload ID Table for Monitor_1 is ruined and > we don't reallocate it. > > [How] > In dm_dp_destroy_mst_connector(), only clean the cur_link_settings when > we no longer do mst mode. > > Signed-off-by: Wayne Lin <Wayne.Lin@xxxxxxx> > --- > drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > 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 2c10352fa514..526f29598403 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 > @@ -415,7 +415,10 @@ static void dm_dp_destroy_mst_connector(struct drm_dp_mst_topology_mgr *mgr, > aconnector->dc_sink); > dc_sink_release(aconnector->dc_sink); > aconnector->dc_sink = NULL; > - aconnector->dc_link->cur_link_settings.lane_count = 0; > + mutex_lock(&mgr->lock); > + if (!mgr->mst_state) > + aconnector->dc_link->cur_link_settings.lane_count = 0; > + mutex_unlock(&mgr->lock); Hi Wayne, The change looks good to me. Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx> Just for curiosity, do you know why we use a mutex instead of spin_lock_irq for this case? FWIU, the spin_lock_irq behavior looks better for this sort of manipulation. Thanks > } > > drm_connector_unregister(connector); > -- > 2.17.1 > -- Rodrigo Siqueira https://siqueira.tech
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