[Qemu-devel] [PULL 1/1] fix microphone lag with PA

[Gerd Hoffmann <kraxel@redhat.com>]

From: Martin Schrodt <martin@schrodt.org>

Several people have reported to have bag microphone lag with the PA
backend. While I cannot reproduce the problem here, it seems that their
PA somehow decides to buffer the microphone input for way too long,
causing this delay. This patch sets an upper limit to the amount of
data PA should hold. This fixes the problem reliably on their side,
while having no adverse effects on mine.

Signed-off-by: Martin Schrodt <martin@schrodt.org>
Message-id: 20190615153852.99040-1-martin@schrodt.org
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 audio/paaudio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/audio/paaudio.c b/audio/paaudio.c
index fa9dd9efd4cc..5fc886bb33cd 100644
--- a/audio/paaudio.c
+++ b/audio/paaudio.c
@@ -618,7 +618,7 @@ static int qpa_init_in(HWVoiceIn *hw, struct audsettings *as, void *drv_opaque)
     ss.rate = as->freq;
 
     ba.fragsize = pa_usec_to_bytes(ppdo->latency, &ss);
-    ba.maxlength = -1;
+    ba.maxlength = pa_usec_to_bytes(ppdo->latency * 2, &ss);
     ba.minreq = -1;
     ba.prebuf = -1;
 
-- 
2.18.1