Bug#462753: libao2: need to clear the final period in alsa driver before closing it.

[Monty Montgomery]

Morita,

I've committed a test fix for the VIA end-of-playback click problem to
xiph.org's libao SVN in revision 16861.  This is using a strategy
different than the one you suggested and I'm interested to see if it
works:

svn co http://svn.xiph.org/trunk/ao -r 16861

It will build and install in /usr/local/lib by default.  The libao in
SVN right now is an API/ABI break from previous releases (though there
are no changes that affect compilation).  Please verify that your test
program sees the right libao library (ldd libaobug | grep libao shold
report libao.so.4 insetad of libao.so.2).

Also, by default libao will not use alsa mmap access; not using mmap
is more likely to work properly.  I would also be interested in
knowing if my changes affect mmap playback for VIA, which was also
previously known to be broken with crackles between every transfer,
due to the same alignment issues.

This can be done in your test program by adding:

  ao_option *o=NULL;
  ao_append_option(&o,"use_mmap","yes");

and passing the option struct to the device open:

  device = ao_open_live(driver_id, &format, o);

Thank you for your time and attention! I look forward to hearing about
the results of both tests.

Monty