Quoting Dmitry Baryshkov (2023-09-03 15:24:32) > diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c b/drivers/gpu/drm/msm/dp/dp_panel.c > index 97ba41593820..1cb54f26f5aa 100644 > --- a/drivers/gpu/drm/msm/dp/dp_panel.c > +++ b/drivers/gpu/drm/msm/dp/dp_panel.c > @@ -162,6 +162,11 @@ int dp_panel_read_sink_caps(struct dp_panel *dp_panel, > } > } > > + rc = drm_dp_read_downstream_info(panel->aux, dp_panel->dpcd, > + dp_panel->downstream_ports); > + if (rc) > + return rc; I haven't been able to test it yet, but I think with an apple dongle we'll never populate the 'downstream_ports' member if the HDMI cable is not connected when this runs. That's because this function bails out early before trying to read the downstream ports when there isn't a sink. Perhaps we need to read it again when an hpd_irq comes in, or we need to read it before bailing out from here?
