lib32/lib32-alsa-plugins/Add_handle_underrun_option.patch
2010-11-27 22:08:16 +00:00

87 lines
2.9 KiB
Diff

From: Takashi Iwai <tiwai@suse.de>
Date: Fri, 9 Jul 2010 12:05:03 +0000 (+0200)
Subject: pulse: Add handle_underrun option
X-Git-Url: http://git.alsa-project.org/?p=alsa-plugins.git;a=commitdiff_plain;h=c20d516e229620129ee20175d8fee8511cc3a4bd
pulse: Add handle_underrun option
Added a config option "handle_underrun" to specify whether pulse plugin
handles the underrun reported from PA. The default value is now set to
false, i.e. it will ignore underruns in PA (for good reasons below).
You can take back to the old behavior by setting handle_underrun true.
The original idea was brought by David Henningsson <diwic@ubuntu.com>,
while this patch is simplified and makes the behavior configurable.
The reasons for avoiding underruns (cited from David's original patch):
Reporting underruns to ALSA seems to do more bad than good, for these reasons:
* If pulseaudio gets an underrun, the normal way to end that underrun is to
feed it with more buffers. This is different from the ALSA way of dealing
with underruns, which requires hardware buffer pointers to be reset.
* In addition, underrun signals are delivered asynchronously from pulseaudio.
This means that there might be more buffers on the way to pulseaudio when
the underrun is reported, making the underrun obsolete. Unfortunately,
there is currently no known way to determine whether this is the case or
not.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
diff --git a/pulse/pcm_pulse.c b/pulse/pcm_pulse.c
index b322898..2df0a80 100644
--- a/pulse/pcm_pulse.c
+++ b/pulse/pcm_pulse.c
@@ -39,6 +39,7 @@ typedef struct snd_pcm_pulse {
size_t last_size;
size_t ptr;
int underrun;
+ int handle_underrun;
size_t offset;
@@ -696,8 +697,9 @@ static int pulse_prepare(snd_pcm_ioplug_t * io)
if (io->stream == SND_PCM_STREAM_PLAYBACK) {
pa_stream_set_write_callback(pcm->stream,
stream_request_cb, pcm);
- pa_stream_set_underflow_callback(pcm->stream,
- stream_underrun_cb, pcm);
+ if (pcm->handle_underrun)
+ pa_stream_set_underflow_callback(pcm->stream,
+ stream_underrun_cb, pcm);
r = pa_stream_connect_playback(pcm->stream, pcm->device,
&pcm->buffer_attr,
PA_STREAM_AUTO_TIMING_UPDATE |
@@ -980,6 +982,7 @@ SND_PCM_PLUGIN_DEFINE_FUNC(pulse)
snd_config_iterator_t i, next;
const char *server = NULL;
const char *device = NULL;
+ int handle_underrun = 0;
int err;
snd_pcm_pulse_t *pcm;
@@ -1005,6 +1008,14 @@ SND_PCM_PLUGIN_DEFINE_FUNC(pulse)
}
continue;
}
+ if (strcmp(id, "handle_underrun") == 0) {
+ if ((err = snd_config_get_bool(n)) < 0) {
+ SNDERR("Invalid value for %s", id);
+ return -EINVAL;
+ }
+ handle_underrun = err;
+ continue;
+ }
SNDERR("Unknown field %s", id);
return -EINVAL;
}
@@ -1028,6 +1039,8 @@ SND_PCM_PLUGIN_DEFINE_FUNC(pulse)
goto error;
}
+ pcm->handle_underrun = handle_underrun;
+
err = pulse_connect(pcm->p, server);
if (err < 0)
goto error;