[PATCH] alsa-plugins: Pulse: only underrun if no more data has been written

[David Henningsson]

If more data has already been written after the underrun, the underrun
will automatically end and therefore we should not report it or
restart the stream.

Signed-off-by: David Henningsson <david.henningsson at canonical.com>
---
 configure.in      |    7 +++++++
 pulse/pcm_pulse.c |   28 ++++++++++++++++++++++++++--
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/configure.in b/configure.in
index ccf59ba..f6886b1 100644
--- a/configure.in
+++ b/configure.in
@@ -31,8 +31,14 @@ AC_ARG_ENABLE([pulseaudio],
 
 if test "x$enable_pulseaudio" != "xno"; then
   PKG_CHECK_MODULES(pulseaudio, [libpulse >= 0.9.11], [HAVE_PULSE=yes], [HAVE_PULSE=no])
+  PKG_CHECK_MODULES(pulseaudio_099, [libpulse >= 0.99.1], 
+    [HAVE_PULSE_UNDERRUN_INDEX=yes], [HAVE_PULSE_UNDERRUN_INDEX=no])
+  
 fi
 AM_CONDITIONAL(HAVE_PULSE, test x$HAVE_PULSE = xyes)
+if test "$HAVE_PULSE_UNDERRUN_INDEX" = "yes"; then
+  AC_DEFINE([HAVE_PULSE_UNDERRUN_INDEX], 1, Pulseaudio underrun index available)
+fi 
 
 AC_ARG_ENABLE([samplerate],
       AS_HELP_STRING([--disable-samplerate], [Disable building of samplerate plugin]))
@@ -185,6 +191,7 @@ echo "Pulseaudio plugin:  $HAVE_PULSE"
 if test "$HAVE_PULSE" = "yes"; then
   echo "  pulseaudio_CFLAGS: $pulseaudio_CFLAGS"
   echo "  pulseaudio_LIBS: $pulseaudio_LIBS"
+  echo "  pulseaudio underrun index: $HAVE_PULSE_UNDERRUN_INDEX" 
 fi
 echo "Samplerate plugin:  $HAVE_SAMPLERATE"
 if test "$HAVE_SAMPLERATE" = "yes"; then
diff --git a/pulse/pcm_pulse.c b/pulse/pcm_pulse.c
index d6c6792..61f1c0c 100644
--- a/pulse/pcm_pulse.c
+++ b/pulse/pcm_pulse.c
@@ -26,6 +26,10 @@
 #include <alsa/asoundlib.h>
 #include <alsa/pcm_external.h>
 
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
 #include "pulse.h"
 
 typedef struct snd_pcm_pulse {
@@ -39,9 +43,10 @@ typedef struct snd_pcm_pulse {
 	size_t last_size;
 	size_t ptr;
 	int underrun;
-	int handle_underrun;
+	int handle_underrun; /* can be 0=never, 1=always or 2,3=only if more data has not been written */
 
 	size_t offset;
+	int64_t written;
 
 	pa_stream *stream;
 
@@ -459,6 +464,7 @@ static snd_pcm_sframes_t pulse_write(snd_pcm_ioplug_t * io,
 	}
 
 	/* Make sure the buffer pointer is in sync */
+	pcm->written += writebytes;
 	pcm->last_size -= writebytes;
 	ret = update_ptr(pcm);
 	if (ret < 0)
@@ -594,7 +600,12 @@ static void stream_underrun_cb(pa_stream * p, void *userdata)
 	if (!pcm->p)
 		return;
 
-	pcm->underrun = 1;
+	if (pcm->handle_underrun == 1
+#ifdef HAVE_PULSE_UNDERRUN_INDEX
+		|| pcm->written <= pa_stream_get_underflow_index(p)
+#endif
+	)
+		pcm->underrun = 1;
 }
 
 static void stream_latency_cb(pa_stream *p, void *userdata) {
@@ -691,6 +702,7 @@ static int pulse_prepare(snd_pcm_ioplug_t * io)
 		goto finish;
 	}
 
+	pcm->written = 0;
 	pa_stream_set_state_callback(pcm->stream, stream_state_cb, pcm);
 	pa_stream_set_latency_update_callback(pcm->stream, stream_latency_cb, pcm);
 
@@ -983,7 +995,11 @@ SND_PCM_PLUGIN_DEFINE_FUNC(pulse)
 	const char *server = NULL;
 	const char *device = NULL;
 	const char *fallback_name = NULL;
+#ifdef HAVE_PULSE_UNDERRUN_INDEX
+	int handle_underrun = 2;
+#else
 	int handle_underrun = 0;
+#endif
 	int err;
 	snd_pcm_pulse_t *pcm;
 
@@ -1017,6 +1033,14 @@ SND_PCM_PLUGIN_DEFINE_FUNC(pulse)
 			handle_underrun = err;
 			continue;
 		}
+		if (strcmp(id, "handle_underrun_detect") == 0) {
+			if ((err = snd_config_get_bool(n)) < 0) {
+				SNDERR("Invalid value for %s", id);
+				return -EINVAL;
+			}
+			handle_underrun = err ? handle_underrun | 2 : handle_underrun & ~2;
+			continue;
+		}
 		if (strcmp(id, "fallback") == 0) {
 			if (snd_config_get_string(n, &fallback_name) < 0) {
 				SNDERR("Invalid value for %s", id);
-- 
1.7.5.4


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