Re: [PATCH] drm/bridge: tc358767: Support input format negotiation hook

[Tomi Valkeinen]

On 31/10/2023 14:18, Jan Kiszka wrote:
> On 31.10.23 11:53, Tomi Valkeinen wrote:
> > Hi Jan,
> >
> > On 31/10/2023 08:24, Jan Kiszka wrote:
> > > On 30.10.23 20:28, Aradhya Bhatia wrote:
> > > > With new connector model, tc358767 will not create the connector, when
> > > > DRM_BRIDGE_ATTACH_NO_CONNECTOR is set and display-controller driver will
> > > > rely on format negotiation to setup the encoder format.
> > > >
> > > > Add the missing input-format negotiation hook in the
> > > > drm_bridge_funcs to complete DRM_BRIDGE_ATTACH_NO_CONNECTOR support.
> > > >
> > > > Input format is selected to MEDIA_BUS_FMT_RGB888_1X24 as default, as is
> > > > the case with older model.
> > > >
> > > > Reported-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
> > > > Signed-off-by: Aradhya Bhatia <a-bhatia1@xxxxxx>
> > > > ---
> > > >
> > > > Notes:
> > > >
> > > >     * Since I do not have hardware with me, this was just build
> > > > tested. I would
> > > >       appreciate it if someone could test and review it, especically
> > > > somebody, who
> > > >       uses the bridge for DPI/DSI to eDP format conversion.
> > > >
> > > >     * The Toshiba TC358767 bridge is not enabled in arm64 defconfig by
> > > > default,
> > > >       when it should be. Hence, I sent a quick patch[0] earlier.
> > > >
> > > > [0]:
> > > > https://lore.kernel.org/all/20231030152834.18450-1-a-bhatia1@xxxxxx/
> > > >
> > > >    drivers/gpu/drm/bridge/tc358767.c | 25 +++++++++++++++++++++++++
> > > >    1 file changed, 25 insertions(+)
> > > >
> > > > diff --git a/drivers/gpu/drm/bridge/tc358767.c
> > > > b/drivers/gpu/drm/bridge/tc358767.c
> > > > index ef2e373606ba..0affcefdeb1c 100644
> > > > --- a/drivers/gpu/drm/bridge/tc358767.c
> > > > +++ b/drivers/gpu/drm/bridge/tc358767.c
> > > > @@ -1751,6 +1751,30 @@ tc_dpi_atomic_get_input_bus_fmts(struct
> > > > drm_bridge *bridge,
> > > >        return input_fmts;
> > > >    }
> > > >    +static u32 *
> > > > +tc_edp_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
> > > > +                 struct drm_bridge_state *bridge_state,
> > > > +                 struct drm_crtc_state *crtc_state,
> > > > +                 struct drm_connector_state *conn_state,
> > > > +                 u32 output_fmt,
> > > > +                 unsigned int *num_input_fmts)
> > > > +{
> > > > +    u32 *input_fmts;
> > > > +
> > > > +    *num_input_fmts = 0;
> > > > +
> > > > +    input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts),
> > > > +                 GFP_KERNEL);
> > > > +    if (!input_fmts)
> > > > +        return NULL;
> > > > +
> > > > +    /* This is the DSI/DPI-end bus format */
> > > > +    input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
> > > > +    *num_input_fmts = 1;
> > > > +
> > > > +    return input_fmts;
> > > > +}
> > > > +
> > > >    static const struct drm_bridge_funcs tc_dpi_bridge_funcs = {
> > > >        .attach = tc_dpi_bridge_attach,
> > > >        .mode_valid = tc_dpi_mode_valid,
> > > > @@ -1777,6 +1801,7 @@ static const struct drm_bridge_funcs
> > > > tc_edp_bridge_funcs = {
> > > >        .atomic_duplicate_state =
> > > > drm_atomic_helper_bridge_duplicate_state,
> > > >        .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
> > > >        .atomic_reset = drm_atomic_helper_bridge_reset,
> > > > +    .atomic_get_input_bus_fmts = tc_edp_atomic_get_input_bus_fmts,
> > > >    };
> > > >      static bool tc_readable_reg(struct device *dev, unsigned int reg)
> > > >
> > > > base-commit: c503e3eec382ac708ee7adf874add37b77c5d312
> > >
> > > Doesn't help, callback is never invoked. There must be more missing.
> > >
> > > Regarding test setup: Maybe your colleague Preneeth can help to give you
> > > access, he just received some devices from us. Otherwise, drop me
> > > instrumentation patches.
> >
> > Can you try with this change:
> >
> > 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);
> >   }
> >
> >   Tomi
>
> Yep, that does the trick.

Alright, good. I'll send a proper patch.

> Thanks,
> Jan
>
> PS: Your mail client is mangling tabs - was already suspecting our
> server would reformat again.

Nah, the above was just a quick copy paste from my terminal window, and 
when copying from the terminal it's always just spaces.

 Tomi