pulseaudio: process audio data in smaller chunks

The rate of pulseaudio absorbing the audio stream is used to control the
the rate of the guests audio stream.  When the emulated hardware uses
small chunks (like intel-hda does) we need small chunks on the audio
backend side too, otherwise that feedback loop doesn't work very well.

Cc: Max Ehrlich <maxehr@umiacs.umd.edu>
Cc: Martin Schrodt <martin@schrodt.org>
Buglink: https://bugs.launchpad.net/bugs/1795527Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20181109142032.1628-1-kraxel@redhat.com

audio/paaudio.c

@@ -227,7 +227,7 @@ static void *qpa_thread_out (void *arg)
             }
         }
 
-        decr = to_mix = audio_MIN (pa->live, pa->g->conf.samples >> 2);
+        decr = to_mix = audio_MIN(pa->live, pa->g->conf.samples >> 5);
         rpos = pa->rpos;
 
         if (audio_pt_unlock(&pa->pt, __func__)) {
@@ -319,7 +319,7 @@ static void *qpa_thread_in (void *arg)
             }
         }
 
-        incr = to_grab = audio_MIN (pa->dead, pa->g->conf.samples >> 2);
+        incr = to_grab = audio_MIN(pa->dead, pa->g->conf.samples >> 5);
         wpos = pa->wpos;
 
         if (audio_pt_unlock(&pa->pt, __func__)) {