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authorRicardo Biehl Pasquali <pasqualirb@gmail.com>2019-03-12 16:31:04 -0300
committerRicardo Biehl Pasquali <pasqualirb@gmail.com>2019-04-24 10:57:57 -0300
commitc6c0d788a835277b190d267fa4d6b338e4bba30e (patch)
tree1e999eb3ceca6d111dd431f236074030d710381d /src
parent1d2302a566935bf213f4f110a7f98c8f8a655d07 (diff)
pcm: Allow to wait if capture is not running
This allows starting capture from another thread. See the commit 932a81519572 ("ALSA: pcm: Comment why read blocks when PCM is not running") in Linux kernel. Signed-off-by: Ricardo Biehl Pasquali <pasqualirb@gmail.com>
Diffstat (limited to 'src')
-rw-r--r--src/pcm.c21
1 files changed, 10 insertions, 11 deletions
diff --git a/src/pcm.c b/src/pcm.c
index 4710862..a32871e 100644
--- a/src/pcm.c
+++ b/src/pcm.c
@@ -1282,17 +1282,16 @@ int pcm_mmap_transfer(struct pcm *pcm, void *buffer, unsigned int frames)
return -1;
state = pcm->mmap_status->state;
- /* start capture if frames >= threshold */
- if (!is_playback && state == PCM_STATE_PREPARED) {
- if (frames >= pcm->config.start_threshold) {
- err = ioctl(pcm->fd, SNDRV_PCM_IOCTL_START);
- if (err == -1)
- return -1;
- /* state = PCM_STATE_RUNNING */
- } else {
- /* nothing to do */
- return 0;
- }
+ /*
+ * If frames < start_threshold, wait indefinitely.
+ * Another thread may start capture
+ */
+ if (!is_playback && state == PCM_STATE_PREPARED &&
+ frames >= pcm->config.start_threshold) {
+ err = ioctl(pcm->fd, SNDRV_PCM_IOCTL_START);
+ if (err == -1)
+ return -1;
+ /* state = PCM_STATE_RUNNING */
}
avail = pcm_mmap_avail(pcm);