[pulseaudio-discuss] cannot control input devices from pavucontrol + crashes in recording tab

Peter Hercek phercek at gmail.com
Wed Dec 22 07:47:54 PST 2010

On 12/22/2010 03:27 PM, Colin Guthrie wrote:
> 'Twas brillig, and Maarten Bosmans at 22/12/10 12:20 did gyre and gimble:
>> 2010/12/22 Peter Hercek<phercek at gmail.com>:
>>> Well that says it alll. When I try to control muting or levels of input
>>> deviced in pavucontrol then it does not work. I can do this with 'alsamixer
>>> -c 0'. I use archlinux and I set pulseaudio based on this page:
>>> https://wiki.archlinux.org/index.php/PulseAudio
>>> I also read
>>> http://www.pulseaudio.org/wiki/PerfectSetup
>>> and it did not seem to contain something which would help.
>>> Playback, Output Devices and Configuration tabs seem to work well.
>>> Recording tab results in a pavucontrol crash when I try to mute a microphone
>>> which is used by arecord.
>>> Anything I do in Input Devices does not seem to have any effect.
>> [In order to look into the crash, a backtrace would be nice to have
>> (don't forget to install debug symbols of all the relevant libraries)]
> Yeah a backtraces from pavucontrol would be nice to aid debugging here.
> I tried to reproduce here but it didn't crash...
> Tho' as I think about it, there should not be a mute on the Recording
> tab.... There is no stream volume (or mute) on source outputs (recording
> streams), only playback (I did start support to add this to source
> outputs but didn't get very far before I found something more
> interesting to do!)
> So the bug is really that pavucontrol even offers you a mute there at
> all! I'll fix that.
Ok, that would mean that removing the button fixes the crash. I need to 
press it to make pavucontrol crash.
Here is the backtrace in case you are still interested (I did not use 
your patch you posted later).
The crash happens when I press the mute button. And I was wrong before I 
did not crash when I pressed the mute button on the arecord source 
(arecord uses alsa plug-in of pulseaudio) ... or maybe it did but I 
cannot reproduce it any more; but it crashed (and still crashes) when I 
press the mute button on VBox source (a virtual box instance running a 
windows image).
And the backtrace:
(gdb) bt
#0  0x000000000040caf2 in StreamWidget::onMuteToggleButton() ()
#1  0x00007ffff6ead762 in 
Glib::SignalProxyNormal::slot0_void_callback(_GObject*, void*) () from 
#2  0x00007ffff5fe1ebe in g_closure_invoke () from 
#3  0x00007ffff5ff39e2 in ?? () from /usr/lib/libgobject-2.0.so.0
#4  0x00007ffff5ffcc45 in g_signal_emit_valist () from 
#5  0x00007ffff5ffce13 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#6  0x00007ffff641de2d in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#7  0x00007ffff77f9900 in 
Gtk::Button_Class::released_callback(_GtkButton*) () from 
#8  0x00007ffff5fe1ebe in g_closure_invoke () from 
#9  0x00007ffff5ff2fcc in ?? () from /usr/lib/libgobject-2.0.so.0
#10 0x00007ffff5ffcc45 in g_signal_emit_valist () from 
#11 0x00007ffff5ffce13 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#12 0x00007ffff62af9cd in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#13 0x00007ffff789c454 in 
Gtk::Widget::on_button_release_event(_GdkEventButton*) () from 
#14 0x00007ffff789fb13 in 
_GdkEventButton*) () from /usr/lib/libgtkmm-2.4.so.1
#15 0x00007ffff63593a8 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#16 0x00007ffff5fe1ebe in g_closure_invoke () from 
#17 0x00007ffff5ff3618 in ?? () from /usr/lib/libgobject-2.0.so.0
#18 0x00007ffff5ffc9e5 in g_signal_emit_valist () from 
#19 0x00007ffff5ffce13 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#20 0x00007ffff647481f in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#21 0x00007ffff6357563 in gtk_propagate_event () from 
#22 0x00007ffff6357913 in gtk_main_do_event () from 
#23 0x00007ffff3f4c64c in ?? () from /usr/lib/../lib/libgdk-x11-2.0.so.0
#24 0x00007ffff5d2ebf3 in g_main_context_dispatch () from 
#25 0x00007ffff5d2f3d0 in ?? () from /usr/lib/libglib-2.0.so.0
#26 0x00007ffff5d2fa42 in g_main_loop_run () from /usr/lib/libglib-2.0.so.0
#27 0x00007ffff6356917 in gtk_main () from /usr/lib/libgtk-x11-2.0.so.0
#28 0x00007ffff7833275 in Gtk::Main::run(Gtk::Window&) () from 
#29 0x00000000004202d8 in main ()

To tell the truth I do not really care that much about the crash as I 
would like to be able to control Line-In mute/volume from pavucontrol 
... now I'm not sure whether I want something which is possible. I'll 
send another post to your parent about this.

>> Why are you using arecord? That way you bypass PulseAudio completely
>> and record directly from the alsa sound source. Using parec instead
>> gives you all the pulse goodies you can handle!
> Actually arecord will typically use the "default" PCM which should be
> mapped to pulseaudio in any sensible setup. It should work fine (it does
> here).
Yes I have it mapped to pulse.

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