[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Fri, 2 Feb 2024 16:49:04 +0100
From: Maxime Ripard <mripard@...nel.org>
To: Sebastian Wick <sebastian.wick@...hat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>,
Daniel Vetter <daniel@...ll.ch>, Emma Anholt <emma@...olt.net>, Jonathan Corbet <corbet@....net>,
Sandy Huang <hjc@...k-chips.com>, Heiko Stübner <heiko@...ech.de>,
Chen-Yu Tsai <wens@...e.org>, Jernej Skrabec <jernej.skrabec@...il.com>,
Samuel Holland <samuel@...lland.org>, linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
dri-devel@...ts.freedesktop.org, Hans Verkuil <hverkuil@...all.nl>,
linux-rockchip@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
linux-arm-kernel@...ts.infradead.org, linux-media@...r.kernel.org
Subject: Re: 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
Download attachment "signature.asc" of type "application/pgp-signature" (229 bytes)
Powered by blists - more mailing lists