[gstreamer-bugs] [Bug 478512] [alsamixer] volume control slider not working

[GStreamer (bugzilla.gnome.org)]

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  GStreamer | gst-plugins-base | Ver: git

Antoine Tremblay changed:

           What    |Removed                     |Added
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                 CC|                            |hexa00 at gmail.com




------- Comment #32 from Antoine Tremblay  2009-02-03 21:43 UTC -------
This is due to race conditions between functions that modified the mixer like
set_volume and snd_mixer_handle_events since the handle_events can now be
called at any time.

Fixed by adding locking around any snd_mixer call since even read functions can
modify the mixer stucture. (Since alsa likes to clear it's values before
reading new ones)

The favorite race condition seemed to be that set_volume called read_elem (in
alsalib) that reset the volumes to 0 and then read them with read_x_volume.
This read looped on each channel and as the race condition occured the channels
value could be anything , most of the time it was 0.. Thus no value was read or
only the value of one channel was and the volume
was reset to 0.

Note that I also cleaned up the poll code...


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