[PATCHv4 1/9] video: add hotplug detect notifier support

[Russell King - ARM Linux]

On Mon, Feb 27, 2017 at 06:21:05PM +0100, Hans Verkuil wrote:
> On 02/27/2017 06:04 PM, Russell King - ARM Linux wrote:
> > I'm afraid that I walked away from this after it became clear that there
> > was little hope for any forward progress being made in a timely manner
> > for multiple reasons (mainly the core CEC code being out of mainline.)
> 
> In case you missed it: the core CEC code was moved out of staging and into
> mainline in 4.10.

I was aware (even though I've not been publishing anything, I do keep
dw-hdmi-cec and tda9950/tda998x up to date with every final kernel
release.)

> > If you can think of a better approach, then I'm sure there's lots of
> > people who'd be willing to do the coding for it... if not, I'm not
> > sure where we go from here (apart from keeping code in private/vendor
> > trees.)
> 
> For CEC there are just two things that it needs: the physical address
> (contained in the EDID) and it needs to be informed when the EDID disappears
> (typically due to a disconnect), in which case the physical address
> becomes invalid (f.f.f.f).

Yep.  CEC really only needs to know "have new phys address" and
"disconnect" provided that CEC drivers understand that they may receive
a new phys address with no intervening disconnect.  (Consider the case
where EDID changes, but the HDMI driver failed to spot the HPD signal
pulse - unfortunately, there's hardware out there where HPD is next to
useless.)

> Russell, do you have pending code that needs the ELD support in the
> notifier?  CEC doesn't need it, so from my perspective it can be
> dropped in the first version.

I was looking for that while writing the previous mail, and I think
it's time to drop it - I had thought dw-hdmi-*audio would use it, or
the ASoC people, but it's still got no users, so I think it's time
to drop it.

I have seen some patch sets go by which are making use of the notifier,
but I haven't paid close attention to how they're using it or what
they're using it for... as I sort of implied in my previous mail, I
had lost interest in mainline wrt CEC stuff due to the glacial rate
of progress.  (That's not a criticism.)

-- 
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