From: Timo Wischer twischer@de.adit-jv.com
Without this fix the application pointer would be reseted whenever an application opens a device with SND_PCM_APPEND.
This would result in an Xrun if the device is already opened and in running state and the appl_ptr is use.
Signed-off-by: Timo Wischer twischer@de.adit-jv.com
diff --git a/src/pcm/pcm_hw.c b/src/pcm/pcm_hw.c index b93926c..65b198c 100644 --- a/src/pcm/pcm_hw.c +++ b/src/pcm/pcm_hw.c @@ -1004,16 +1004,28 @@ static int map_status_and_control_data(snd_pcm_t *pcm, bool force_fallback) hw->sync_ptr = NULL; }
- /* Initialize the data. */ - hw->mmap_control->appl_ptr = 0; - hw->mmap_control->avail_min = 1; + /* do not initialize in case of append and keep the values from the + * kernel + */ + if (!(pcm->mode & SND_PCM_APPEND)) { + /* Initialize the data. */ + hw->mmap_control->appl_ptr = 0; + hw->mmap_control->avail_min = 1; + } snd_pcm_set_hw_ptr(pcm, &hw->mmap_status->hw_ptr, hw->fd, SNDRV_PCM_MMAP_OFFSET_STATUS + offsetof(struct snd_pcm_mmap_status, hw_ptr)); snd_pcm_set_appl_ptr(pcm, &hw->mmap_control->appl_ptr, hw->fd, SNDRV_PCM_MMAP_OFFSET_CONTROL); if (hw->mmap_control_fallbacked) { - err = sync_ptr1(hw, 0); + unsigned int flags; + /* read appl_ptr and avail_min from kernel when device opened + * with SND_PCM_APPEND flag + */ + if (pcm->mode & SND_PCM_APPEND) + flags = SNDRV_PCM_SYNC_PTR_APPL | + SNDRV_PCM_SYNC_PTR_AVAIL_MIN; + err = sync_ptr1(hw, flags); if (err < 0) return err; } @@ -1539,6 +1551,8 @@ int snd_pcm_hw_open_fd(snd_pcm_t **pcmp, const char *name, int fd, mode |= SND_PCM_NONBLOCK; if (fmode & O_ASYNC) mode |= SND_PCM_ASYNC; + if (fmode & O_APPEND) + mode |= SND_PCM_APPEND;
if (ioctl(fd, SNDRV_PCM_IOCTL_PVERSION, &ver) < 0) { ret = -errno;