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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