[PATCH v3 06/14] Documentation: drm/bridge: add document for analogix_dp

Russell King - ARM Linux linux at arm.linux.org.uk
Mon Aug 24 05:57:58 PDT 2015

On Sun, Aug 23, 2015 at 06:23:14PM -0500, Rob Herring wrote:
> On Wed, Aug 19, 2015 at 9:50 AM, Yakir Yang <ykk at rock-chips.com> wrote:
> > +       -analogix,color-depth:
> > +               number of bits per colour component.
> > +                       COLOR_6 = 0, COLOR_8 = 1, COLOR_10 = 2, COLOR_12 = 3
> This seems pretty generic. Just use 6, 8, 10, or 12 for values. And
> drop the vendor prefix.

Please think about this some more.  What does "color-depth" mean?  Does it
mean the number of bits per colour _component_, or does it mean the total
number of bits to represent a particular colour.  It's confusing as it

> > +Optional properties for dp-controller:
> > +       -analogix,hpd-gpio:
> > +               Hotplug detect GPIO.
> > +                       Indicates which GPIO should be used for hotplug
> > +                       detection
> We should align with "hpd-gpios" used by HDMI connector binding. Or do
> we need a DP connector binding that this should be defined in?
> Probably so.
> The DRM related bindings are such a cluster f*ck with everyone picking
> their own way to do things. Just grep hpd in bindings for starters.
> That is just the tip.

I'm not surprised one iota that DRM bindings are a mess.  There's no one
overlooking the adoption of DRM bindings, so surprise surprise, everyone
does their own thing.  This is exactly what happens every time in that
scenario.  It's not a new problem.

When we adopted the graph bindings for iMX DRM, I thought exactly at that
time "it would be nice if this could become the standard for binding DRM
components together" but I don't have the authority from either the DT
perspective or the DRM perspective to mandate that.  Neither does anyone
else.  That's the _real_ problem here.

I've seen several DRM bindings go by which don't use the of-graph stuff,
which means that they'll never be compatible with generic components
which do use the of-graph stuff.

Like you say, it's a mess, but it's a mess of our own making, because no
one has the authority to regulate this.

FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up
according to speedtest.net.

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