[Qemu-devel] [PATCH] audio: Fix support for multiple soft output voices.

[digit@google.com]

From: David 'Digit' Turner <digit@google.com>

This patch fixes a minor bug that prevent audio emulation from working
properly when several soft output voices are opened. The symptom was that
as long as one active soft voice was empty, it prevented any output from
any other voice.

More precisely, audio_pcm_hw_find_min_out always returns 0 with a value
of nb_livep > 0, which later forced the playback of exactly 0 hardware
samples to the audio backend (which of course didn't do anything).

By ignoring empty voices, we can let the active samples of other voices
pass through normally.
---
 audio/audio.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/audio/audio.c b/audio/audio.c
index ad51077..c7888c0 100644
--- a/audio/audio.c
+++ b/audio/audio.c
@@ -968,7 +968,7 @@ static int audio_pcm_hw_find_min_out (HWVoiceOut *hw, int *nb_livep)
     int nb_live = 0;
 
     for (sw = hw->sw_head.lh_first; sw; sw = sw->entries.le_next) {
-        if (sw->active || !sw->empty) {
+        if (sw->active && !sw->empty) {
             m = audio_MIN (m, sw->total_hw_samples_mixed);
             nb_live += 1;
         }
@@ -1411,7 +1411,7 @@ static void audio_run_out (AudioState *s)
 
         cleanup_required = 0;
         for (sw = hw->sw_head.lh_first; sw; sw = sw->entries.le_next) {
-            if (!sw->active && sw->empty) {
+            if (!sw->active || sw->empty) {
                 continue;
             }
 
@@ -1514,7 +1514,7 @@ static void audio_run_capture (AudioState *s)
         hw->rpos = rpos;
 
         for (sw = hw->sw_head.lh_first; sw; sw = sw->entries.le_next) {
-            if (!sw->active && sw->empty) {
+            if (!sw->active || sw->empty) {
                 continue;
             }
 
-- 
1.7.3.1