david.henningsson at canonical.com
Mon Jul 29 14:42:08 UTC 2013
On 07/29/2013 04:06 PM, Len Ovens wrote:
> On Sun, July 28, 2013 10:34 pm, Jarno Suni wrote:
>> 2013/7/29 Len Ovens <len at ovenwerks.net>
>>> Interesting... I did some testing. Turning pulse off in the session
>>> up does not keep it from starting. Second, The pulse configuration does
>>> not stay where it is put. Plugging in headphones takes a HW device that
>>> turned off turns it on in pulse (I think this is a bug). Anything at all
>>> that tries to communicate with pulse using dbus starts pulse even if it
>>> turned off. While pulse has a device turned off, you are right the alsa
>>> mixer works as intended.
>> So did you do the "autospawn = no" trick told in the original post?
> Autospawn = no would be ineffective. dbus gets in the way. For example if
> you plug in a new USB interface or even plug headphones in, ubuntu is set
> up to tell pulse via dbus of these changes so that pulse can change the
> levels correctly. Dbus will autostart any application it is trying to talk
> to if it is not running.
This is wrong.
PulseAudio, when it is already running, monitors udev/uevents to know
when new sound cards have appeared.
That's all. There is nothing trying to start PulseAudio when a new card
is plugged in. And PulseAudio is never started as a request from dBus.
PulseAudio will be autospawned if a client tries to access it, and this
can be prohibited with autospawn = no.
In some older releases PulseAudio was also started in the
start-pulseaudio-x11 script (which is executed on X login, through
/etc/xdg/autostart/pulseaudio.desktop), but this is now removed - I
don't remember which release.
Looking at 12.04, all start-pulseaudio-x11 has got is pactl commands,
(which would just output errors if pulseaudio isn't running and
> The only way to keep pulse from starting is to
> remove the x bit from the file name.
I would strongly recommend against this technique, because if you want
pulseaudio to be running again and you forgot how you disabled it, it
will be quite difficult to find.
> I will try it anyway just to be sure,
> pulse would have to look at who was starting it and decide not to start if
> it's parent was dbus. That doesn't make sense as dbus is the normal way of
> starting pulse. A device profile that tells pulse to do software levels
> only (as it does with jack or other multi-track cards like the ice1712)
> would probably work better.
David Henningsson, Canonical Ltd.
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