[pulseaudio-discuss] [PATCH 0/3] Read HDMI ELD info and set a port property

[Fengguang Wu]

On Sun, Feb 17, 2013 at 09:07:24AM +0100, David Henningsson wrote:
> On 02/17/2013 02:29 AM, Fengguang Wu wrote:
> >Hi David,
> >
> >On Fri, Feb 15, 2013 at 11:02:31PM -0600, Pierre-Louis Bossart wrote:
> >>
> >>>There's a bummer though. On the one machine I've tested this, the ELD is not
> >>>immediately available, so hotplugging doesn't work. It also looks like there's no
> >>>event being sent out from the kernel when ELD has become available, so we probably
> >
> >You may print a debug messages in the graphics driver's interrupt handler
> >for every hotplug event to check if the hotplug event is not raised
> >from hardware at all, or (likely) get lost somewhere later when
> >passing it to the audio driver.
> >
> >>>need to add some kind of timer - but I'm not sure exactly what time ranges should
> >>>work for all machines. Pierre, do you know?
> >>
> >>Trying rebooting with the HDMI cable plugged and see if this works.
> >>I know my IbexPeak hardware only detects HDMI at boot, probably some
> >>BIOS issue. Fengguang might be able to help?
> >
> >Good tip. It's worth trying, as I noticed the same phenomenon in my
> >past HDMI tests (HDMI not useable at all if hot-plugged after boot).
> >For the boot issue, it may be because of some unknown BIOS hack, or
> >something the graphics driver failed to initialize (or did it right).
> 
> To clarify: When hotplugging, the ELD does show up, it just doesn't
> do that at the same time as the jack does, that is, eld might become
> valid at a later time compared to the "precense" bit.
> 
> I looked at the kernel code now, and it seems like there is a repoll
> mechanism to fetch the ELD information. It shouldn't be too
> difficult to insert a snd_ctl_notify when the ELD control changes
> (as Tanu suggests), I will look into this next week hopefully.

Yeah I added the repoll code. It's beyond me why the repoll is
necessary at all...

Thanks,
Fengguang