Quoting Sankeerth Billakanti (2022-04-22 02:11:05) > The source device should ensure the sink is ready before proceeding to > read the sink capability or perform any aux transactions. The sink > will indicate its readiness by asserting the HPD line. The controller > driver needs to wait for the hpd line to be asserted by the sink before > it performs any aux transactions. > > The eDP sink is assumed to be always connected. It needs power from the > source and its HPD line will be asserted only after the panel is powered > on. The panel power will be enabled from the panel-edp driver and only > after that, the hpd line will be asserted. > > Whereas for DP, the sink can be hotplugged and unplugged anytime. The hpd > line gets asserted to indicate the sink is connected and ready. Hence > there is no need to wait for the hpd line to be asserted for a DP sink. > > Signed-off-by: Sankeerth Billakanti <quic_sbillaka@xxxxxxxxxxx> > Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx> > --- Reviewed-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
