[PATCH 02/13] drm/connector: Add helper to check if a mode requires scrambling

[Daniel Vetter]

On Thu, Nov 04, 2021 at 05:37:21PM +0200, Ville Syrjälä wrote:
> On Tue, Nov 02, 2021 at 03:59:33PM +0100, Maxime Ripard wrote:
> > --- a/include/drm/drm_modes.h
> > +++ b/include/drm/drm_modes.h
> > @@ -424,6 +424,21 @@ static inline bool drm_mode_is_stereo(const struct drm_display_mode *mode)
> >  	return mode->flags & DRM_MODE_FLAG_3D_MASK;
> >  }
> >  
> > +/**
> > + * drm_mode_hdmi_requires_scrambling - Checks if a mode requires HDMI Scrambling
> > + * @mode: DRM display mode
> > + *
> > + * Checks if a given display mode requires the scrambling to be enabled.
> > + *
> > + * Returns:
> > + * A boolean stating whether it's required or not.
> > + */
> > +static inline bool
> > +drm_mode_hdmi_requires_scrambling(const struct drm_display_mode *mode)
> > +{
> > +	return mode->clock > DRM_HDMI_14_MAX_TMDS_CLK_KHZ;
> > +}
> 
> That's only correct for 8bpc. The actual limit is on the TMDS clock (or
> rather TMDS character rate as HDMI 2.0 calls it due to the 1/1 vs. 1/4
> magic for the actually transmitted TMDS clock).

Yeah we might need to add the bus format for the cable here too, to make
this complete.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch