On Mon, 12 Feb 2024 17:50:36 +0100 Sebastian Wick <sebastian.w...@redhat.com> wrote:
> On Mon, Feb 12, 2024 at 11:10:15AM +0200, Pekka Paalanen wrote: > > On Fri, 9 Feb 2024 17:53:07 +0100 > > Xaver Hugl <xaver.h...@kde.org> wrote: > > > > > Signed-off-by: Xaver Hugl <xaver.h...@kde.org> > > > --- > > > drivers/gpu/drm/drm_connector.c | 8 ++++++++ > > > 1 file changed, 8 insertions(+) > > > > > > diff --git a/drivers/gpu/drm/drm_connector.c > > > b/drivers/gpu/drm/drm_connector.c > > > index b0516505f7ae..01e13984629b 100644 > > > --- a/drivers/gpu/drm/drm_connector.c > > > +++ b/drivers/gpu/drm/drm_connector.c > > > @@ -2158,6 +2158,14 @@ > > > EXPORT_SYMBOL(drm_mode_create_aspect_ratio_property); > > > * one supported. Sink supported colorspaces should be retrieved by > > > * userspace from EDID and driver will not explicitly expose them. > > > * > > > + * As userspace can't currently know whether or not the output is > > > using > > > + * RGB or YCC signalling, the driver must translate properties to > > > their > > > + * relevant RGB or YCC counterparts, depending on the actually used > > > + * signalling. Property values that are only valid for either YCC or > > > RGB > > > + * and have no equivalent for the other signalling type must not be > > > + * exposed as supported, unless the driver can guarantee it never > > > uses > > > + * the signalling that doesn't match the property. > > > + * > > > * Basically the expectation from userspace is: > > > * - Set up CRTC DEGAMMA/CTM/GAMMA to convert to some sink > > > * colorspace > > > > While this addition is good, I have another question: > > > > Does "Colorspace" property choose also the RGB->YCbCr matrix that the > > driver will use when it happens to use YCbCr signalling? > > > > So far we have only been talking about the primaries and white point. > > Uh, yeah, good point. The InfoFrames do affect both the YCbCr conversion > and the transfer characteristics that the sink expects. Drivers should > do the RGB to YCbCr conversion with the new matrix. I think (and very > much hope) that drivers don't rely on the TF for any internal processing > but if they did, they also should use the one the sink expects. Oh, is transfer function also somehow associated here? That would be a third thing. Are there any "Colorspace" values that target a display with not gamma 2.2 TF (possibly extended/mirrored)? The only TF metadata control I've known so far is the one in HDR_OUTPUT_METADATA. Thanks, pq
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