[alsa-devel] [PATCH] ALSA: HDA: Add jack detection for HDMI

[Takashi Iwai]

At Sat, 21 May 2011 08:25:57 +0200,
David Henningsson wrote:
> 
> On 2011-05-20 23:59, Stephen Warren wrote:
> > David Henningsson wrote at Tuesday, May 17, 2011 7:47 AM:
> >> Just as for headphones and microphone jacks, this patch adds reporting
> >> of HDMI jack status through the input layer.
> >>
> >> I considered making additional SND_JACK_* constants for HDMI and
> >> Displayport instead of going with SND_JACK_VIDEOOUT, but it didn't seem
> >> worth the additions, and breakage of compiling with old kernels, etc.
> >> Let me know if you think otherwise and I'll prepare a second patch for
> >> that.
> >
> > One more thought on this:
> >
> > Some of our older HW (MCP6x, MCP7x chipsets) doesn't support unsolicited
> > responses, nor PD/ELDV/ELD data. If PulseAudio is updated to listen to
> > these new jack events on kernels where the input files are present,
> > that'll presumably cause it never to allow use of the HDMI sinks on those
> > chipsets. I don't know if other vendors have this issue or not.
> >
> > In that case, can we do one of:
> >
> > * Not create the jack/input files at all.
> >
> > * Immediately mark the jack as "present".
> >
> > I assume the latter would be easier for user-space to deal with; it'd be
> > more in line with the kernel abstracting HW differences.
> >
> 
> Ok, thanks for the input (no pun intended ;-) ). If they support 
> presence detect, we could create a polling loop. Otherwise, don't create 
> the jack.

In that case, input-polldev would be an option, too.
Of course, this will need some change in the input-jack layer.


Takashi