[PATCH 2/4] drm/bridge: dw-hdmi: add cec notifier support

[Russell King - ARM Linux]

On Mon, Jul 17, 2017 at 10:56:47AM +0200, Hans Verkuil wrote:
> Hi Russell,
> 
> On 09/06/17 16:10, Russell King - ARM Linux wrote:
> > On Fri, Jun 09, 2017 at 03:56:39PM +0200, Neil Armstrong wrote:
> >> Yes, but on the Amlogic Meson plarform, the DW-HDMI CEC controller is
> >> not used, but a custom one, so this notifier is actually useful for
> >> this platform and maybe others.
> > 
> > Is the CEC controller configured into dw-hdmi (is the config bit set?)
> > I'm just wondering if we're going to end up with two CEC drivers trying
> > to bind to the same notifier.
> > 
> >> Should we really wait until I push the Amlogic AO CEC driver ? Having a
> >> notifier in the DW-HDMI driver won't harm anybody since it *will be used*.
> > 
> > It sounds like this adds additional information that has been missing
> > from the review of my patches - and I suspect changes Hans' comments.
> > So, I'll wait, it seems pointless to try and update the patches when
> > it's not clear how to proceed due to other dependencies, especially
> > when it means that their existing state is what's required (I'm pleased
> > that I've held off modifying the patches so far.)
> > 
> > If that means having to wait another kernel revision, then I guess that's
> > what will have to happen.
> 
> Can you respin your patch series, keeping the notifier support? The CEC
> kernel config handling has been cleaned up (just select CEC_CORE and
> CEC_NOTIFIER) so you should be good to go.

Not yet - the change to the way you're dealing with Kconfig in CEC is
fundamentally broken, and needs fixing before we can merge dw-hdmi-cec
support.

As a result of these Kconfig changes, dw-hdmi-cec now fails if:

1. You build the CEC part as a module
2. You build the HDMI part into the kernel

This results in CEC_NOTIFIER=y and CEC_CORE=m, which, when the HDMI part
gets built, results in the stubs in the notifier code being used, rather
than the real functions.  This in turn causes the CEC part to never
receive a physical address, which is therefore non-functional.

I did have a patch to fix this, but it was never committed, and I got
busy with other stuff (so it ended up being git reset --hard away.)

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