[pulseaudio-discuss] internal speaker silent in Asus eee netbook (patch)

[Guenter Milde]

Dear Tanu,

On Thu Oct 12 Tanu Kaskinen wrote:
> On Mon, 2017-10-09 at 18:45 +0200, Guenter Milde wrote:
> > On Sat Aug 5 Tanu Kaskinen tanuk at iki.fi wrote:

> > What is the difference between "switch = off" and "switch = mute"?
...
> "switch = off" means that PulseAudio sets the switch to off. "switch =
> mute" means that the switch state follows the sink mute state. If you
> set the Headphone element switch to "mute" in the speaker path, then
> headphones will be unmuted when the sink is unmuted while having the
> speaker port active.

My test shows that with "switch=mute", I can toggle the mute-state of
speaker and headphones independently. Unmuting the speaker does
not unmute the headphones and vice versa. So while there is a chance to make
both, speaker and headphones active, this requires very specific user action.

> analog-output-speaker used to have "switch = mute" for Headphone, but
> that was changed in this commit:
> https://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/?id=22aac4e9fdb3786178f7815a0cb2150f588b1582

The reason given there is a bit different but valid.
I agree that generally, it is preferable to switch off the headphone control
if headphones are not plugged in.
However, if the alternative is not any sound from the speakers, muting
the headphones (instead of switching off) is still an acceptable
workaround. Without the patch, there is:

  a) no sound with headphones plugged (expected, no signal in the meter),
  b) no sound after booting without headphones
     (despite a visible signal in pa-mixer's  speaker meter),
  c) no sound after after unplugging headphones
     (despite a visible signal in pa-mixer's  speaker meter).

With the patch, there may be a somewhat longer spike in the headphones when
plugged in under some situations but otherwise, both speakers and headphone
work as one would expect.

> analog-output-speaker-always should have been changed at the same time,
> but that was forgotten.

OK.

> As I said in my previous mail, this is an alsa bug. Please report the
> issue to the alsa developers:
> https://alsa-project.org/main/index.php/Bug_Tracking

I will try this.

> If your bug report gets ignored, then we can add a workaround in
> PulseAudio, but instead of depending on a bug in the analog-output-
> speaker-always configuration, a new path configuration file will be
> needed 

I agree that a separate config file is preferable and volunteer to provide
a patch.

> for intentionally leaving headphones unmuted when using speakers.

The point is not to leave headphones *unmuted* when using speakers but to
mute them instead of switching them off.


BTW:

When changing analog-output-speaker-always.conf, please check which rules
in /lib/udev/rules.d/90-pulseaudio.rules use "force-speaker.conf" or
"force-speaker-and-int-mic.conf" to work around the problem of no speaker
output with "switch = off". At least for the Asus 904HA (1000H) EeePC, it
is very probable that it suffers from the same problem as the Asus R11CX
and R011PX tested here. These rules should be changed to use a new
"never-turn-off-speakers" profile set (together with new rules for the
Asus EeePC R11CX and Asus EeePC R011PX).
If we could establish this as a problem of a particular sound driver
module, it would be good to write just one udev rule based on the module
instead of the subsystem_device attribute.

Günter