[alsa-devel] Headphone issues iMac 14.1 (A1418)

[Takashi Iwai]

On Thu, 04 Jan 2018 17:27:55 +0100,
Freaky wrote:
> 
> Hi Takashi,
> 
> we need it to get the headphone output working. Upon unplugging /
> replugging we need to check them again (they remain checked, but the output
> stops working). The speaker output (onboard speakers) works fine and the
> script we run doesn't appear to have any effect on the speaker output at
> all.

The alsa-info.sh output showed that GPIO[1] is also set, so I wonder
how and who sets it.  In anyway, could you check whether flipping any
such gpio bits turn on / off the headphone and the speaker outputs?
Try to toggle it while playing back, such as,
	hda-verb /dev/snd/hwC1D0 0x01 SET_GPIO_DATA xxx
where xxx is the value to be written (0x00, 0x02, 0x04, 0x06, etc).

> Currently use a python script generated by the HDA Analyzer script that we
> run every 5 seconds from boot. Pasted the script below. We run it every 5
> seconds to ensure audio will work after replugging the headphones (although
> it might incur a small delay then of course). I don't notice any hick-ups
> in audio playback because of the script firing every 5 seconds.
> 
> There's no acpid running from which we could detect the plug event. Using a
> system based on Fedora 24. Have watched dbus-monitor (--sytem), but see no
> events there upon (un)plugging the headphones which we could use as trigger.

The headphone jack detection on HD-audio is usually done via HD-audio
codec unsolicited events.  You can check "Headphone Jack" ALSA control
element (e.g. watch the output of "amixer contents").


Takashi