Fix a rpos coordination bug between qpa_run_out() and qpa_thread_out(),
which shows up as playback noises.
qpa_run_out()
qpa_thread_out loop N critical section 1
qpa_run_out() qpa_thread_out loop N doing pa_simple_write()
qpa_run_out() qpa_thread_out loop N doing pa_simple_write()
qpa_thread_out loop N critical section 2
qpa_thread_out loop N+1 critical section 1
qpa_run_out() qpa_thread_out loop N+1 doing pa_simple_write()
In the above scheme, "qpa_thread_out loop N+1 critical section 1" will
get the same rpos as the one used by "qpa_thread_out loop N critical
section 1". So it will be reading dead samples from the old rpos.
The rpos can only be updated back to qpa_thread_out when there is a
qpa_run_out() run between two qpa_thread_out loops.
normal sequence:
qpa_thread_out:
hw->rpos (X0) => local rpos => pa->rpos (X1)
qpa_run_out:
pa->rpos (X1) => hw->rpos (X1)
qpa_thread_out:
hw->rpos (X1) => local rpos => pa->rpos (X2)
buggy sequence:
qpa_thread_out:
hw->rpos (X0) => local rpos => pa->rpos (X1)
qpa_thread_out:
hw->rpos (X0) => local rpos => pa->rpos (X1')
Obviously qpa_run_out() shall be called at least once between any two
qpa_thread_out loops (after pa->rpos is set), in order for the new
qpa_thread_out loop to see the updated rpos.
Setting pa->live to 0 does the trick. The next loop will have to wait
for one qpa_run_out() invocation in order to get a non-zero pa->live
and proceed.
Signed-off-by: malc <av1474@comtv.ru>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
We're seeing various issues with the SDL audio backend and want to
switch to the pulseaudio backend. See e.g.
https://bugzilla.redhat.com/495964https://bugzilla.redhat.com/519540https://bugzilla.redhat.com/496627
The pulseaudio backend seems to work well, so we should allow it to be
selected as the default.
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: malc <av1474@comtv.ru>
pcm_ops.run_out now takes number of live samples (which will be always
greater than zero) as a second argument, every driver was calling
audio_pcm_hw_get_live_out anyway with exception of fmod which used
audio_pcm_hw_get_live_out2 for no good reason.
Signed-off-by: malc <av1474@comtv.ru>
