Fix buffer size handling of direct plugins

Introduce "max_periods" option to specify the max number of periods
per buffer to each plugin.

- When max_periods = -1, the fixed buffer size as the slave size is
  used (old behavior).
- When max_periods = 0 (or 1), the number of periods is variable
  between 2 and the slave buffer size.
- When max_periods greater than 2 is given, it specifies the max
  periods of that pcm explicitly.

When no option is given in the PCM defintion, the value
"defaults.pcm.dmix_max_periods" is referred as default.
The default value is 0, as defined in alsa.conf.
You can override this in ~/.asoundrc or /etc/asound.conf as you like.

1 files changed, 2 insertions, 10 deletions

diff --git a/src/pcm/pcm_dsnoop.c b/src/pcm/pcm_dsnoop.c
index 8ef83494..4d44e76f 100644
--- a/src/pcm/pcm_dsnoop.c
+++ b/src/pcm/pcm_dsnoop.c
@@ -544,7 +544,7 @@ int snd_pcm_dsnoop_open(snd_pcm_t **pcmp, const char *name,
 	pcm->private_data = dsnoop;
 	dsnoop->state = SND_PCM_STATE_OPEN;
 	dsnoop->slowptr = opts->slowptr;
-	dsnoop->variable_buffer_size = opts->variable_buffer_size;
+	dsnoop->max_periods = opts->max_periods;
 	dsnoop->sync_ptr = snd_pcm_dsnoop_sync_ptr;
 
 	if (first_instance) {
@@ -707,10 +707,9 @@ int _snd_pcm_dsnoop_open(snd_pcm_t **pcmp, const char *name,
 	struct slave_params params;
 	struct snd_pcm_direct_open_conf dopen;
 	int bsize, psize;
-	int ipc_offset;
 	int err;
 
-	err = snd_pcm_direct_parse_open_conf(conf, &dopen);
+	err = snd_pcm_direct_parse_open_conf(root, conf, stream, &dopen);
 	if (err < 0)
 		return err;
 
@@ -741,13 +740,6 @@ int _snd_pcm_dsnoop_open(snd_pcm_t **pcmp, const char *name,
 	params.period_size = psize;
 	params.buffer_size = bsize;
 
-	ipc_offset = snd_pcm_direct_get_slave_ipc_offset(root, sconf, stream);
-	if (ipc_offset < 0) {
-		snd_config_delete(sconf);
-		return ipc_offset;
-	}
-	dopen.ipc_key += ipc_offset;
-
 	err = snd_pcm_dsnoop_open(pcmp, name, &dopen, &params,
 				  root, sconf, stream, mode);
 	if (err < 0)