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Commit e4f5d6bd authored by Eric Wong's avatar Eric Wong Committed by Max Kellermann
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alsa: re-enable-nonblocking, but sleep if busy

Instead of letting ALSA block for us (and potentially allowing something stupid on certain hardware or drivers), we do the sleeping ourselves. We calculate the sleep to be a fraction of period_time to avoid oversleeping (and thus audible skipping).
parent 9899ab5a
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Showing with 10 additions and 7 deletions
src/audioOutputs/audioOutput_alsa.c
View file @ e4f5d6bd
...@@ -37,9 +37,6 @@ static const char default_device[] = "default"; ...@@ -37,9 +37,6 @@ static const char default_device[] = "default";
#include <alsa/asoundlib.h> #include <alsa/asoundlib.h>
/* #define MPD_SND_PCM_NONBLOCK SND_PCM_NONBLOCK */
#define MPD_SND_PCM_NONBLOCK 0
typedef snd_pcm_sframes_t alsa_writei_t(snd_pcm_t * pcm, const void *buffer, typedef snd_pcm_sframes_t alsa_writei_t(snd_pcm_t * pcm, const void *buffer,
snd_pcm_uframes_t size); snd_pcm_uframes_t size);
...@@ -49,6 +46,7 @@ typedef struct _AlsaData { ...@@ -49,6 +46,7 @@ typedef struct _AlsaData {
alsa_writei_t *writei; alsa_writei_t *writei;
unsigned int buffer_time; unsigned int buffer_time;
unsigned int period_time; unsigned int period_time;
unsigned int period_sleep;
int sampleSize; int sampleSize;
int useMmap; int useMmap;
} AlsaData; } AlsaData;
...@@ -160,18 +158,16 @@ static int alsa_openDevice(struct audio_output *audioOutput) ...@@ -160,18 +158,16 @@ static int alsa_openDevice(struct audio_output *audioOutput)
ad->device, audioFormat->bits); ad->device, audioFormat->bits);
err = snd_pcm_open(&ad->pcmHandle, ad->device, err = snd_pcm_open(&ad->pcmHandle, ad->device,
SND_PCM_STREAM_PLAYBACK, MPD_SND_PCM_NONBLOCK); SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
if (err < 0) { if (err < 0) {
ad->pcmHandle = NULL; ad->pcmHandle = NULL;
goto error; goto error;
} }
#if MPD_SND_PCM_NONBLOCK == SND_PCM_NONBLOCK
cmd = "snd_pcm_nonblock"; cmd = "snd_pcm_nonblock";
err = snd_pcm_nonblock(ad->pcmHandle, 0); err = snd_pcm_nonblock(ad->pcmHandle, 0);
if (err < 0) if (err < 0)
goto error; goto error;
#endif /* MPD_SND_PCM_NONBLOCK == SND_PCM_NONBLOCK */
period_time_ro = period_time = ad->period_time; period_time_ro = period_time = ad->period_time;
configure_hw: configure_hw:
...@@ -254,6 +250,8 @@ configure_hw: ...@@ -254,6 +250,8 @@ configure_hw:
if (retry != MPD_ALSA_RETRY_NR) if (retry != MPD_ALSA_RETRY_NR)
DEBUG("ALSA period_time set to %d\n", period_time); DEBUG("ALSA period_time set to %d\n", period_time);
ad->period_sleep = period_time >> 1;
cmd = "snd_pcm_hw_params_get_buffer_size"; cmd = "snd_pcm_hw_params_get_buffer_size";
err = snd_pcm_hw_params_get_buffer_size(hwparams, &alsa_buffer_size); err = snd_pcm_hw_params_get_buffer_size(hwparams, &alsa_buffer_size);
if (err < 0) if (err < 0)
...@@ -388,7 +386,12 @@ static int alsa_playAudio(struct audio_output *audioOutput, ...@@ -388,7 +386,12 @@ static int alsa_playAudio(struct audio_output *audioOutput,
while (size > 0) { while (size > 0) {
ret = ad->writei(ad->pcmHandle, playChunk, size); ret = ad->writei(ad->pcmHandle, playChunk, size);
if (ret == -EAGAIN || ret == -EINTR) if (ret == -EAGAIN) {
DEBUG("ALSA busy, sleeping %d\n", ad->period_sleep);
my_usleep(ad->period_sleep);
continue;
}
if (ret == -EINTR)
continue; continue;
if (ret < 0) { if (ret < 0) {
......
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