On 31-Oct-23 18:56, Tomi Valkeinen wrote: > When a display controller driver uses DRM_BRIDGE_ATTACH_NO_CONNECTOR, > tc358767 will behave properly and skip the creation of the connector. > > However, tc_get_display_props(), which is used to find out about the DP > monitor and link, is only called from two places: .atomic_enable() and > tc_connector_get_modes(). The latter is only used when tc358767 creates > its own connector, i.e. when DRM_BRIDGE_ATTACH_NO_CONNECTOR is _not_ > set. > > Thus, the driver never finds out the link properties before get_edid() > is called. With num_lanes of 0 and link_rate of 0 there are not many > valid modes... > > Fix this by adding tc_connector_get_modes() call at the beginning of > get_edid(), so that we have up to date information before looking at the > modes. > > Reported-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> > Closes: https://lore.kernel.org/all/24282420-b4dd-45b3-bb1c-fc37fe4a8205@xxxxxxxxxxx/ > Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx> > --- Thank you, Tomi, for quickly debugging this! Reviewed-by: Aradhya Bhatia <a-bhatia1@xxxxxx> Regards Aradhya > drivers/gpu/drm/bridge/tc358767.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c > index 0affcefdeb1c..137a9f5e3cad 100644 > --- a/drivers/gpu/drm/bridge/tc358767.c > +++ b/drivers/gpu/drm/bridge/tc358767.c > @@ -1579,6 +1579,13 @@ static struct edid *tc_get_edid(struct drm_bridge *bridge, > struct drm_connector *connector) > { > struct tc_data *tc = bridge_to_tc(bridge); > + int ret; > + > + ret = tc_get_display_props(tc); > + if (ret < 0) { > + dev_err(tc->dev, "failed to read display props: %d\n", ret); > + return 0; > + } > > return drm_get_edid(connector, &tc->aux.ddc); > } >
