Re: [PATCH v4 1/2] drm/connector: hdmi: Add a 'link bpc' property

[Maxime Ripard]

Hi,

On Wed, Mar 11, 2026 at 12:30:55PM +0100, Nicolas Frattaroli wrote:
> Display drivers may degrade from higher bit depths to lower bit depths
> for reasons such as bandwidth constraints. Userspace applications, such
> as compositors, may wish to know that this has occurred transparently,
> instead of assuming that the "max bpc" they requested could be reached.
> 
> Introduce a new immutable DRM property called "link bpc" that reflects
> the current display link's bits-per-component. An uevent is fired when
> the link bpc value changes.
> 
> Set the new link_bpc member in the HDMI state helper to its HDMI output
> bpc, so that during the next commit, the property is updated accordingly
> and the uevent is fired.
> 
> Co-developed-by: Derek Foreman <derek.foreman@xxxxxxxxxxxxx>
> Signed-off-by: Derek Foreman <derek.foreman@xxxxxxxxxxxxx>
> Co-developed-by: Marius Vlad <marius.vlad@xxxxxxxxxxxxx>
> Signed-off-by: Marius Vlad <marius.vlad@xxxxxxxxxxxxx>
> Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@xxxxxxxxxxxxx>

I feel like this should be two separate patches: one to create the
property, and another to hook it into the HDMI helpers.

With that fixed, and for both patches that will come out of this one,
Acked-by: Maxime Ripard <mripard@xxxxxxxxxx>

Maxime

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