[18/23] paaudio: limit minreq to 75% of audio timer_rate

Commit Message

Volker Rümelin Jan. 10, 2021, 10:02 a.m. UTC

Currently with the playback buffer attribute minreq = -1 and flag
PA_STREAM_EARLY_REQUESTS PulseAudio uses minreq = tlength / 4.
To improve audio playback with larger PulseAudio server side
buffers, limit minreq to a maximum of 75% of audio timer_rate.
That way there is a good chance qemu receives a stream buffer
size update before it tries to write data to the playback stream.

Signed-off-by: Volker Rümelin <[e-mail]>
---
 audio/paaudio.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Patch

diff --git a/audio/paaudio.c b/audio/paaudio.c
index ff3dd01c96..3186868294 100644
--- a/audio/paaudio.c
+++ b/audio/paaudio.c
@@ -517,7 +517,8 @@  static int qpa_init_out(HWVoiceOut *hw, struct audsettings *as,
     ss.rate = as->freq;
 
     ba.tlength = pa_usec_to_bytes(ppdo->latency, &ss);
-    ba.minreq = -1;
+    ba.minreq = pa_usec_to_bytes(MIN(ppdo->latency >> 2,
+                                     (g->dev->timer_period >> 2) * 3), &ss);
     ba.maxlength = -1;
     ba.prebuf = -1;