On Thu, 16 Mar 2023 12:47:51 +0200
Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote:
> On Thu, Mar 16, 2023 at 12:07:01PM +0200, Pekka Paalanen wrote:
> > On Thu, 16 Mar 2023 11:50:27 +0200
> > Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote:
> >
> > > On Thu, Mar 16, 2023 at 01:37:24AM +0100, Sebastian Wick wrote:
> > > > On Tue, Mar 7, 2023 at 4:12 PM Harry Wentland <harry.wentland@xxxxxxx> wrote:
> > > > >
> > > > > We want compositors to be able to set the output
> > > > > colorspace on DP and HDMI outputs, based on the
> > > > > caps reported from the receiver via EDID.
> > > >
> > > > About that... The documentation says that user space has to check the
> > > > EDID for what the sink actually supports. So whatever is in
> > > > supported_colorspaces is just what the driver/hardware is able to set
> > > > but doesn't actually indicate that the sink supports it.
> > > >
> > > > So the only way to enable bt2020 is by checking if the sink supports
> > > > both RGB and YUV variants because both could be used by the driver.
> > > > Not great at all. Something to remember for the new property.
> > >
> > > Hmm. I wonder if that's even legal... Looks like maybe it
> > > is since I can't immediately spot anything in CTA-861 to
> > > forbid it :/
> >
> > Wouldn't the driver do the same EDID check before choosing whether it
> > uses RGB or YCbCr signalling?
>
> I suppose it could. The modeset would then fail, which is perhaps
Could? What are they missing?
I mean, drivers are already automatically choosing between RGB and YCbCr
signalling based on e.g. available bandwidth. Surely they already will
not attempt to send a signal format to a monitor that does not say it
supports that?
> not a huge issue, except maybe for suspend+resume if we fail in
> the resume path. Although I guess the EDID/etc. should not yet
> be refreshed at that point so if the modeset worked before suspend
> resume should be able to restore it without failures.
I assumed that if a monitor can be driven, and it supports any BT2020
format, then it always supports the BT2020 format it is being driven
in (RGB vs. YCbCr flavors). Bad assumption?
Thanks,
pq
> >
> > So if EDID says only one of them is supported, userspace should be
> > confident that that is the BT2020 mode the driver will match?
> >
> >
> > Thanks,
> > pq
> >
> > >
> > > >
> > > > > Signed-off-by: Harry Wentland <harry.wentland@xxxxxxx>
> > > > > Cc: Pekka Paalanen <ppaalanen@xxxxxxxxx>
> > > > > Cc: Sebastian Wick <sebastian.wick@xxxxxxxxxx>
> > > > > Cc: Vitaly.Prosyak@xxxxxxx
> > > > > Cc: Joshua Ashton <joshua@xxxxxxxxx>
> > > > > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> > > > > Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
> > > > > Reviewed-By: Joshua Ashton <joshua@xxxxxxxxx>
> > > > > ---
> > > > > drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 15 +++++++++++++++
> > > > > 1 file changed, 15 insertions(+)
> > > > >
> > > > > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > > > > index f91b2ea13d96..2d883c6dae90 100644
> > > > > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > > > > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > > > > @@ -7184,6 +7184,12 @@ static int amdgpu_dm_connector_get_modes(struct drm_connector *connector)
> > > > > return amdgpu_dm_connector->num_modes;
> > > > > }
> > > > >
> > > > > +static const u32 supported_colorspaces =
> > > > > + BIT(DRM_MODE_COLORIMETRY_BT709_YCC) |
> > > > > + BIT(DRM_MODE_COLORIMETRY_OPRGB) |
> > > > > + BIT(DRM_MODE_COLORIMETRY_BT2020) |
> > > > > + BIT(DRM_MODE_COLORIMETRY_BT2020_DEPRECATED);
> > > > > +
> > > > > void amdgpu_dm_connector_init_helper(struct amdgpu_display_manager *dm,
> > > > > struct amdgpu_dm_connector *aconnector,
> > > > > int connector_type,
> > > > > @@ -7264,6 +7270,15 @@ void amdgpu_dm_connector_init_helper(struct amdgpu_display_manager *dm,
> > > > > adev->mode_info.abm_level_property, 0);
> > > > > }
> > > > >
> > > > > + if (connector_type == DRM_MODE_CONNECTOR_HDMIA) {
> > > > > + if (!drm_mode_create_hdmi_colorspace_property(&aconnector->base, supported_colorspaces))
> > > > > + drm_connector_attach_colorspace_property(&aconnector->base);
> > > > > + } else if (connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> > > > > + connector_type == DRM_MODE_CONNECTOR_eDP) {
> > > > > + if (!drm_mode_create_dp_colorspace_property(&aconnector->base, supported_colorspaces))
> > > > > + drm_connector_attach_colorspace_property(&aconnector->base);
> > > > > + }
> > > > > +
> > > > > if (connector_type == DRM_MODE_CONNECTOR_HDMIA ||
> > > > > connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> > > > > connector_type == DRM_MODE_CONNECTOR_eDP) {
> > > > > --
> > > > > 2.39.2
> > > > >
> > >
> >
>
>
>
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