Bug 512302 – dev-qt/qt-mobility's QtMultimediaKit hangs if built with pulseaudio but PA isn't running

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description Georg Rudoy 2014-06-03 16:58:40 UTC]

The pulseaudio mainloop is locked initially via the call to pa_threaded_mainloop_lock(), but then it's not unlocked via the pa_threaded_mainloop_unlock() call before calling pa_threaded_mainloop_free() if the connection or context setup fails. Thus, pa_threaded_mainloop_free() freezes.

The proposed patch merely calls pa_threaded_mainloop_unlock() before freeing the main loop.

Reproducible: Always

Steps to Reproduce:
1. Build qt-mobility[multimedia,pulseaudio].
2. Build something using QtMultimediaKit, like lc-azoth-9999[media]
3. Make sure PA daemon is stopped.
4. Try running Azoth.
Actual Results:  
Azoth freezed with a trace like the attached one.

Expected Results:  
Azoth started up and running smoothly.

The bug has been already reported upstream, but it was rejected and I doubt Qt guys will fix it now: https://bugreports.qt-project.org/browse/QTBUG-29742

[Comment 1 Georg Rudoy 2014-06-03 16:58:57 UTC]

Created attachment 378176 [details]
The freeze backtrace.

[Comment 2 Georg Rudoy 2014-06-03 16:59:09 UTC]

Created attachment 378178 [details, diff]
The proposed patch.

[Comment 3 Davide Pesavento (RETIRED) 2014-06-03 17:08:00 UTC]

Thanks Georg. You should submit the patch upstream via gerrit, otherwise the chances that it'll be accepted are zero.

[Comment 4 Georg Rudoy 2014-06-03 17:36:46 UTC]

Thanks, I'll try to figure out their patch inclusion process.

Meanwhile, is there any chance for the inclusion of this patch in Gentoo tree?

[Comment 5 Davide Pesavento (RETIRED) 2014-06-03 18:42:27 UTC]

(In reply to Georg Rudoy from comment #4)
> Meanwhile, is there any chance for the inclusion of this patch in Gentoo
> tree?

Yes, but give me some time, I'm busy with other things atm.

[Comment 6 Georg Rudoy 2014-06-03 18:56:19 UTC]

Sure, that wasn't a way to hurry you, but rather a question about patch inclusion policy. For example, Debian doesn't accept patches to packages that weren't included into upstream's VCS. Some other distros also have quite strict reviewing practices.

Thanks again.

[Comment 7 Davide Pesavento (RETIRED) 2014-07-04 01:19:23 UTC]

Hi Georg, did you manage to submit the patch upstream via gerrit?

[Comment 8 Georg Rudoy 2014-07-11 17:59:15 UTC]

(In reply to Davide Pesavento from comment #7)
> Hi Georg, did you manage to submit the patch upstream via gerrit?

Hi Davide,

Not really. I never did that before, and frankly I'm a little bit lazy to clone the whole Qt repo and follow their clumsy submitting policy.

Moreover, the resolution and comments in the bug ( https://bugreports.qt-project.org/browse/QTBUG-29742 ) make me think that they're not going to accept anything to QtMobility:
> Before Qt 5, QtMultimedia was part of the Qt Mobility project, which is not maintained anymore.

As the bug is related to Qt4, I doubt it's worth it.

[Comment 9 Davide Pesavento (RETIRED) 2014-07-11 18:56:41 UTC]

For the record, this is fixed on qtmultimedia's 5.3 branch as of yesterday https://codereview.qt-project.org/87383

[Comment 10 Davide Pesavento (RETIRED) 2015-06-15 01:07:37 UTC]

Closing wrt comment #9