[Intel-gfx] [v6 03/11] drm/i915/display: Attach HDR property for capable Gen9 devices

[Shankar, Uma]

> -----Original Message-----
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Sent: Tuesday, October 6, 2020 2:36 PM
> To: Shankar, Uma <uma.shankar at intel.com>
> Cc: intel-gfx at lists.freedesktop.org
> Subject: Re: [v6 03/11] drm/i915/display: Attach HDR property for capable Gen9
> devices
> 
> On Mon, Oct 05, 2020 at 09:32:22PM +0000, Shankar, Uma wrote:
> >
> >
> > > -----Original Message-----
> > > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > Sent: Tuesday, September 29, 2020 9:44 PM
> > > To: Shankar, Uma <uma.shankar at intel.com>
> > > Cc: intel-gfx at lists.freedesktop.org
> > > Subject: Re: [v6 03/11] drm/i915/display: Attach HDR property for
> > > capable Gen9 devices
> > >
> > > On Tue, Sep 15, 2020 at 02:30:39AM +0530, Uma Shankar wrote:
> > > > Attach HDR property for Gen9 devices with MCA LSPCON chips.
> > > >
> > > > v2: Cleaned HDR property attachment logic based on capability as
> > > > per Jani Nikula's suggestion.
> > > >
> > > > Signed-off-by: Uma Shankar <uma.shankar at intel.com>
> > > > ---
> > > >  drivers/gpu/drm/i915/display/intel_lspcon.c | 5 +++++
> > > >  1 file changed, 5 insertions(+)
> > > >
> > > > diff --git a/drivers/gpu/drm/i915/display/intel_lspcon.c
> > > > b/drivers/gpu/drm/i915/display/intel_lspcon.c
> > > > index 5e2d7ca1d20f..fd05210f4405 100644
> > > > --- a/drivers/gpu/drm/i915/display/intel_lspcon.c
> > > > +++ b/drivers/gpu/drm/i915/display/intel_lspcon.c
> > > > @@ -626,6 +626,11 @@ bool lspcon_init(struct intel_digital_port
> > > > *dig_port)
> > > >
> > > >  	lspcon_detect_hdr_capability(lspcon);
> > > >
> > > > +	if (lspcon->hdr_supported)
> > > > +		drm_object_attach_property(&connector->base,
> > > > +					   connector->dev-
> > > >mode_config.hdr_output_metadata_property,
> > > > +					   0);
> > >
> > > Hmm. This hdr capability detection is going to cause us extra grief
> > > when looking at Kai-Heng's patch to defer lspcon detection until
> > > hotplug time. Not quite sure what to do about that though.
> >
> > Yeah Ville, saw your comments and with Kai's change merge, I am
> > thinking how to attach this dynamically.
> 
> Not allowed.
> 
> >
> > Can we just assume that Lspcon will support HDR as is the case in
> > Gen9. We can just attach this unconditionally at init if Lspcon is exposed from
> VBT. Will this be acceptable or Any better ideas ?
> 
> I have no idea what these lspcon chips supports since -ENODOCS.
> 
> The only idea I have is to attempt an early probe for this, and if it fails on some
> chips due to hpd not being asserted so be it.

Hmm, may be we can check for detection here and based on that enable HDR. If its
not detected on any particular chip, let it not get enabled. I feel this can be a good
WA as most of the devices seem to detect it fine. I will float the next version with this
approach.

Thanks Ville.

> >
> > > > +
> > > >  	connector->ycbcr_420_allowed = true;
> > > >  	lspcon->active = true;
> > > >  	DRM_DEBUG_KMS("Success: LSPCON init\n");
> > > > --
> > > > 2.26.2
> > >
> > > --
> > > Ville Syrjälä
> > > Intel
> 
> --
> Ville Syrjälä
> Intel