This patch fixes the comment about 'pcm' field in 'struct
snd_pcm_ioplug' which wrongly refers to snd_pcm_extplug_create().
Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This function can be called without calling snd_pcm_avail_update().
The call to snd_pcm_avail_update() can take some time.
Therefore some developers would not like to call it from a real-time
context (e.g. from JACK client context).
Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This function can be called without calling snd_pcm_avail_update().
The call to snd_pcm_avail_update() can take some time.
Therefore some developers would not like to call it from a real-time
context (e.g. from JACK client context).
Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
if requested by the IO plugin
Without this changes an IO plugin is not able to report
that buffer_size frames were read from the buffer.
When the buffer was full this is a valid action and
has not to be handled as an under run.
For example when the hw_ptr will be updated with
hw_ptr += buffer_size
and it is using the buffer_size as wrap around
hw_ptr %= buffer_size
would result in the same value as before the add operation.
Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Traditionally, many of ALSA library functions are supposed to be
thread-unsafe, and applications are required to take care of thread
safety by themselves. However, people never be careful enough, and
almost all applications fail in this regard.
This patch is an attempt to harden the thread safety in exported PCM
functions in a simplistic way: just wrap some of exported functions
with the pthread mutex of each PCM object. Not all API functions are
wrapped by the mutex since it doesn't make sense. Instead, the
patchset covers only the functions that may be likely called
concurrently. The supposedly thread-safe API functions are marked in
the document.
For achieving the feature, two new fields are added snd_pcm_t when the
option is enabled: thread_safe and lock. The former indicates that
the plugin is thread-safe that doesn't need this workaround and the
latter is the pthread mutex. Currently only hw plugin have
thread_safe=1. So, the most of real-time sensitive apps won't be
influenced by this patchset.
Although the patch covers most of PCM ops, a few snd_pcm_fast_ops are
left without the extra mutex locking: namely, the ones that may have
blocking behavior, i.e. resume, drain, readi, writei, readn and
writen. These are supposed to handle own locking in the callbacks.
Also, if anyone wants to disable this new thread-safe API feature, it
can be still turned off via --disable-thread-safety configure option.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Instead of passing ambiguous integer array, define snd_pcm_chmap_t and
snd_pcm_chmap_query_t so that user can understand more easily which
element is for what.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Some io plug-ins might want to adjust the reported delay value and not
strictly follow the current buffer usage (that's why we have two calls
after all).
Allow them to specify a delay() callback and use the previous behaviour
if they don't.
Signed-off-by: Pierre Ossman <ossman@cendio.se>
- Added protocl version check. The caller of snd_pcm_{io|ext}plug_create()
must fill version field with SND_PCM_{IO|EXT}PLUG_VERSION beforehand.
- Added poll_descriptors and poll_descriptors_count callbacks for ioplug.
