Re: [PATCH 2/7] drm/uAPI: Add "active color format" drm property as feedback for userspace

[Daniel Stone]

Hi,

On Tue, 9 Jan 2024 at 18:12, Andri Yngvason <andri@xxxxxxxxxxx> wrote:
> + * active color format:
> + *     This read-only property tells userspace the color format actually used
> + *     by the hardware display engine "on the cable" on a connector. The chosen
> + *     value depends on hardware capabilities, both display engine and
> + *     connected monitor. Drivers shall use
> + *     drm_connector_attach_active_color_format_property() to install this
> + *     property. Possible values are "not applicable", "rgb", "ycbcr444",
> + *     "ycbcr422", and "ycbcr420".

How does userspace determine what's happened without polling? Will it
only change after an `ALLOW_MODESET` commit, and be guaranteed to be
updated after the commit has completed and the event being sent?
Should it send a HOTPLUG event? Other?

Cheers,
Daniel