Re: [PATCH v4 05/10] drm/bridge: dw-hdmi-qp: Set bridge supported_formats

[Nicolas Frattaroli <nicolas.frattaroli@collabora.com>]

On Tuesday, 18 November 2025 21:00:08 Central European Standard Time Cristian Ciocaltea wrote:
> Hi Nicolas,
> 
> On 11/17/25 9:11 PM, Nicolas Frattaroli wrote:
> > The drm_bridge "supported_formats" member stores a bitmask of supported
> > HDMI output formats if the bridge is in fact an HDMI bridge.
> > 
> > However, until now, the synopsys dw-hdmi-qp driver did not set this
> > member in the bridge it creates.
> > 
> > Set it based on the platform data's supported_formats member, and
> > default to BIT(HDMI_COLORSPACE_RGB) if it's absent, which preserves the
> > previous behaviour.
> > 
> > Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
> > ---
> >  drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> > index fe4c026280f0..cf888236bd65 100644
> > --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> > +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> > @@ -1269,6 +1269,11 @@ struct dw_hdmi_qp *dw_hdmi_qp_bind(struct platform_device *pdev,
> >  		dev_warn(dev, "Set ref_clk_rate to vendor default\n");
> >  	}
> >  
> > +	if (plat_data->supported_formats)
> > +		hdmi->bridge.supported_formats = plat_data->supported_formats;
> 
> This duplicates a change already introduced via commit 1ff27c5929ab
> ("drm/bridge: dw-hdmi-qp: Handle platform supported formats and color depth").

Hmm, looks like I didn't notice that when rebasing onto next-20251117.

(Aside note, that commit is once again lacking from next-20251119,
did it get dropped for some reason or did DRM as a whole not get
pulled into that next version due to a conflict?)

> 
> > +	else
> > +		hdmi->bridge.supported_formats = BIT(HDMI_COLORSPACE_RGB);
> 
> And this one looks redundant as well, since RGB is supposed to be mandatory:
> supported_formats defaults to RGB in drm_bridge_connector_init() if there's no
> HDMI bridge in the pipeline overriding it, while drmm_connector_hdmi_init()
> errors out if supported_formats is unset or doesn't advertise RGB.

Oops, yeah you're right

> 
> Hence I think this patch can be dropped.

Will do! Thanks for the quick review

> 
> Regards,
> Cristian
> 
>