[pulseaudio-discuss] jackdbus module, pulse fails to conform on device reservation API

[Ian Malone]

On 9 November 2012 17:34, Tanu Kaskinen <tanuk at iki.fi> wrote:
> On Tue, 2012-11-06 at 15:58 -0500, Ian Malone wrote:
>> method call sender=:1.110 ->
>> dest=org.freedesktop.ReserveDevice1.Audio1 serial=6
>> path=/org/freedesktop/ReserveDevice1/Audio1;
>> interface=org.freedesktop.ReserveDevice1; member=RequestRelease
>>    int32 2147483647
>> error sender=:1.35 -> dest=:1.110
>> error_name=org.freedesktop.DBus.Error.UnknownMethod reply_serial=6
>>    string "Method "RequestRelease" with signature "i" on interface
>> "org.freedesktop.ReserveDevice1" doesn't exist
>> "
>
> As far as I know, that error message is generated by the application
> that responds to the RequestRelease method call. PulseAudio doesn't have
> code that would generate an error message like that, so it looks like
> it's actually something else that is sending the error. Here the error
> sender is :1.35, which is not very useful, but if you get the
> dbus-monitor log again, you can check with d-feet what application is
> returning that error (in this case you'd check which application
> is :1.35, but that number will probably be different when you try
> again).
>

If I hadn't seen it before I would say that that's exactly the message
I expect a message framework (d-bus here) to generate when the method
wasn't present. And indeed it is:
$  dbus-send --session --print-reply --reply-timeout=2000
--type=method_call --dest=org.freedesktop.ReserveDevice1.Audio1
/org/freedesktop/ReserveDevice1/Audio1
org.freedesktop.ReserveDevice1.RequestRelease int32:5
Error org.freedesktop.DBus.Error.UnknownMethod: Method
"RequestRelease" with signature "i" on interface
"org.freedesktop.ReserveDevice1" doesn't exist

I don't know how to capture this at the command line, so please see
the d-feet shot of this:

https://picasaweb.google.com/lh/photo/Mnty0Ul3ilCN_pB-ctJoD9MTjNZETYmyPJy0liipFm0?feat=directlink

Audio1 is reserved (the service exists), but the object to request a
release for Audio1 doesn't exist. Getting to this state was actually
quite easy:
1. Start into KDE (pulse is set up as normal for Fedora and autostarted).
2. Start d-feet, you may catch the ReserveDevice1 services before they
disappear, but wait till they do.
3. Open the KDE audio setup dialogue and test playback, this causes
pulse to lock the capture device (hw:0 here) and the playback device
(hw:1).
4. Look at the 'reserved' services. Audio1 is reserved, but can't be
released because there's no object to provide the method.

-- 
imalone
http://ibmalone.blogspot.co.uk