Re: [RFC PATCH v2 4/5] drm/msm/dp: replace dp_connector with drm_bridge_connector

[Stephen Boyd <swboyd@chromium.org>]

Quoting Dmitry Baryshkov (2022-02-18 14:32:53)
> On 19/02/2022 00:31, Kuogee Hsieh wrote:
> >
> > On 2/11/2022 2:40 PM, Dmitry Baryshkov wrote:
> >> There is little point in having both connector and root bridge
> >> implementation in the same driver. Move connector's functionality to the
> >> bridge to let next bridge in chain to override it.
> >>
> >> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> >
> > This patch break primary (edp) display
> >
> > -- right half of screen garbled
> >
> > -- screen shift vertically
> >
> > below are error messages seen --
> >
> > [   36.679216] panel-edp soc@0:edp_panel: No display modes
> > [   36.687272] panel-edp soc@0:edp_panel: No display modes
> > [   40.593709] panel-edp soc@0:edp_panel: No display modes
> > [   40.600285] panel-edp soc@0:edp_panel: No display modes
>
> So, before the patch the drm core was getting modes from the
> drm_connector (which means, modes from drm driver itself). With this
> patch the panel-edp tries to get modes.
>
> Could you please check, why panel_edp_get_modes() fails? Assuming that
> you use platform panel-edp binding (rather than 'edp-panel') could you
> please check you have either of the following:
> - ddc bus for EDID?

I don't see anywhere where the ddc pointer is set for the dp bridge in
msm_dp_bridge_init(). Is that required though? I'd think simple panel is
still being used here so reading EDID isn't required.

> - either num_timing or num_modes in your panel desc.
>