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    SubjectRe: Re: [PATCH v5 08/44] drm/connector: hdmi: Add Broadcast RGB property
    Hi Sebastian,

    On Mon, Jan 15, 2024 at 03:33:08PM +0100, Sebastian Wick wrote:
    > > /**
    > > * DOC: HDMI connector properties
    > > *
    > > + * Broadcast RGB
    > > + * Indicates the RGB Quantization Range (Full vs Limited) used.
    > > + * Infoframes will be generated according to that value.
    > > + *
    > > + * The value of this property can be one of the following:
    > > + *
    > > + * Automatic:
    > > + * RGB Range is selected automatically based on the mode
    > > + * according to the HDMI specifications.
    > > + *
    > > + * Full:
    > > + * Full RGB Range is forced.
    > > + *
    > > + * Limited 16:235:
    > > + * Limited RGB Range is forced. Unlike the name suggests,
    > > + * this works for any number of bits-per-component.
    > > + *
    > > + * Drivers can set up this property by calling
    > > + * drm_connector_attach_broadcast_rgb_property().
    > > + *
    >
    > This is a good time to document this in more detail. There might be two
    > different things being affected:
    >
    > 1. The signalling (InfoFrame/SDP/...)
    > 2. The color pipeline processing
    >
    > All values of Broadcast RGB always affect the color pipeline processing
    > such that a full-range input to the CRTC is converted to either full- or
    > limited-range, depending on what the monitor is supposed to accept.
    >
    > When automatic is selected, does that mean that there is no signalling,
    > or that the signalling matches what the monitor is supposed to accept
    > according to the spec? Also, is this really HDMI specific?
    >
    > When full or limited is selected and the monitor doesn't support the
    > signalling, what happens?

    Leaving the YCbCr vs RGB discussion aside, would this be better ?

    * Broadcast RGB (HDMI specific)
    * Indicates the Quantization Range (Full vs Limited) used. The color
    * processing pipeline will be adjusted to match the value of the
    * property, and the Infoframes will be generated and sent accordingly.
    *
    * The value of this property can be one of the following:
    *
    * Automatic:
    * The quantization range is selected automatically based on the
    * mode according to the HDMI specifications (HDMI 1.4b - Section
    * 6.6 - Video Quantization Ranges).
    *
    * Full:
    * Full quantization range is forced.
    *
    * Limited 16:235:
    * Limited quantization range is forced. Unlike the name suggests,
    * this works for any number of bits-per-component.
    *
    * Property values other than Automatic can result in colors being off (if
    * limited is selected but the display expects full), or a black screen
    * (if full is selected but the display expects limited).
    *
    * Drivers can set up this property by calling
    * drm_connector_attach_broadcast_rgb_property().

    Thanks!
    Maxime
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