Commit graph

430 commits

Author SHA1 Message Date
Natanael Copa
adab355f35 cleanup: Use uint*_t instead of u_int*_t everythwere
Use the standard uint{8,16,32,64}_t everywhere instead of the
non-standard u_int{8,16,32,64}_t.

This changes the types in the public headers and removes the u_int*_t
defines. This may break things. However, indentifiers ending with _t are
reserved by POSIX[1]; defining those can lead to undefined behavior.

So if you rely on alsa-lib defining those for you, then you want the
compiler to error so things can be fixed properly.

[1]: http://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_02_02

Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-07-15 09:50:17 +02:00
Natanael Copa
885c64bcc4 cleanup: fix poll.h includes
According POSIX[1] and linux manpage[2] the include is poll.h, not
sys/poll.h.

This fixes the he following compiler warning when build with musl libc:

  /usr/include/sys/poll.h:1:2: warning: #warning redirecting incorrect #include <sys/poll.h> to <poll.h> [-Wcpp]
   #warning redirecting incorrect #include <sys/poll.h> to <poll.h>
    ^~~~~~~

Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-07-12 12:05:37 +02:00
Takashi Iwai
e757a95fc9 conf: Check the availability of PTHREAD_MUTEX_RECURSIVE
Check the availability of PTHREAD_MUTEX_RECURSIVE in configure script
and use it only when possible.  A fairly old version of glibc still
seems working, but just to be sure.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-05-16 16:26:20 +02:00
Takashi Iwai
1cb217ead9 ALSA: pcm: Use recursive mutex
The recent thread-safety pthread implementation caused deadlocks in
some situations, e.g. when an external plugin calls snd_pcm_state() in
its callback.  One can avoid the deadlock by carefully using the
unlocked version, but it's often error-prone, and it might be still
problem with the old binaries.

In this patch, we initialize the pthread mutex as recursive for fixing
such a problem.

Suggested-by: Timo Wischer <twischer@de.adit-jv.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-04-21 20:36:40 +02:00
Andreas Pape
a50496346f pcm: status dump fix timestamp formatting
nanosecond part formatted with %06 will give incorrect/confusing results:

trigger_time: 154.9748287
trigger_time: 154.60109090
trigger_time: 154.110425257

time seems to run backwards...

This patch converts to us before printing
which gives the correct/expected result:

trigger_time: 154.009748
trigger_time: 154.060109
trigger_time: 154.110425

Signed-off-by: Andreas Pape <apape@de.adit-jv.com>
Signed-off-by: Mounesh Sutar <sutar.mounesh@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-02-17 18:40:48 +01:00
Takashi Iwai
e31a3273df pcm: Disable locking in async mode
When PCM is operated in async mode and an async handler calls some PCM
functions with lock during other PCM operations, we may hit a
deadlock.

Although async mode is rarely used, it's still a possible use case.
Disable the locking when the stream is opened in async mode or it's
set to async mode via snd_pcm_async().

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-02-09 17:29:21 +01:00
Takashi Iwai
b5a2c06f6c pcm: Avoid lock for snd_pcm_nonblock()
snd_pcm_nonblock() is called as snd_pcm_abort().  Since
snd_pcm_abort() is called often from a signal handler to clean things
up (e.g. aplay does it), we may face a deadlock if the signal is
raised during the locked operation.

There can be some way to check the deadlock state, but they would cost
much.  Since the race condition of snd_pcm_nonblock() is quite small,
let's just drop the locking inside snd_pcm_nonblock() as a
workaround.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-02-09 17:26:52 +01:00
Takashi Sakamoto
d008e1ac20 pcm: fix wrong document references to PCM APIs which perform direct memory access with frame copying
In a design of ALSA PCM interface, for PCM frame transmission to/from
kernel space, applications can select from two options; direct memory access
or ioctl(2). Available options are decided depending on device capacity and
machine architecture. Applications can get available options by the first
entry of 'struct snd_pcm_hw_params.masks'.

When the mask includes 'SNDRV_PCM_ACCESS_MMAP_xxx', applications can use
direct memory access. For this use case, userspace library has two types
of PCM API. One is to expose a pointer over the memory to start
reading/writing PCM frames. Another is to copy PCM frames between the
memory and a given buffer.

Current documentation includes wrong references to these APIs to describe
their advantages/disadvantages. This confuses application developers
because the references indicate PCM APIs to execute ioctl(2) operation to
read/write PCM frames.

This commit fixes the bug.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2016-12-12 22:36:29 +01:00
Takashi Iwai
ea74ebbe4d pcm: Add the PCM state checks to plugins
I noticed that some plugin codes have no proper PCM state checks and
it results in expected outcomes.  For example, when snd_pcm_drain() is
called for a dmix PCM after calling snd_pcm_drop(), it stalls
unexpectedly.  It's just because its drain callback doesn't expect the
SND_PCM_SETUP state.

We can fix such a bug in each place one by one, but a safer way would
be to filter out all such cases commonly in the PCM API functions
themselves.  This patch adds the PCM state sanity checks to major API
functions so that they return -EBADFD when called in the unexpected
PCM states.

As well as for the thread-safety extension, it'd be a question of the
performance; again at this time, the hw PCM is considered as an
exception, and it has pcm->own_state_check flag set, which means that
the common PCM state checks are skipped.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2016-11-29 16:22:20 +01:00
Takashi Iwai
0fc4b4d17b pcm: Better understandable locking code
The newly added locking code seems to have confused quite a few
people, as "thread_safe=1" may be considered as if the thread-safety
lock has to be turned on.  (It meant that the plugin _is_ thread-safe,
i.e. it needs no extra locking.)

For avoiding such a misunderstanding, this commit renames the relevant
pcm fields and give more comments to explain what is for what.
The former single pcm->thread_safe flag is now split to two boolean
flags, pcm->need_lock and pcm->lock_enabled.  It consumes a few more
bytes, but this would be (hopefully) better understandable.

No functional change by this commit.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2016-09-02 10:13:48 +02:00
Takashi Sakamoto
f889a8d5de pcm: remove alloca() from snd_pcm_get_params
Both of alloca() and automatic variables keeps storages on stack, while
the former generates more instructions than the latter. It's better to use
the latter if the size of storage is computable at pre-compile or compile
time; i.e. just for structures.

This commit obsolete usages of alloca() with automatic variables.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2016-07-14 16:33:47 +02:00
Takashi Sakamoto
8c3ffab39e pcm: change code formatting for snd_pcm_get_params()
This commit applies code format according to typical and moderate rule,
for snd_pcm_get_params().

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2016-07-14 16:33:47 +02:00
Takashi Sakamoto
a5f54c1aeb pcm: remove alloca() from snd_pcm_set_params()
Both of alloca() and automatic variables keeps storages on stack, while
the former generates more instructions than the latter. It's better to use
the latter if the size of storage is computable at pre-compile or compile
time; i.e. just for structures.

This commit obsolete usages of alloca() with automatic variables.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2016-07-14 16:33:46 +02:00
Takashi Sakamoto
804312cf3e pcm: change code formatting for snd_pcm_set_params()
This commit applies code format according to typical and moderate rule,
for snd_pcm_set_params().

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2016-07-14 16:33:46 +02:00
Takashi Sakamoto
4c124b0759 pcm: fix missing return value of snd_pcm_status()
In former commits for thread-safe PCM APIs, snd_pcm_status() lost its
return value.

This commit regain it.

Fixes: 54931e5a5455('pcm: Add thread-safety to PCM API')
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2016-07-13 16:34:30 +02:00
Takashi Iwai
c4b690278e pcm: Add LIBASOUND_THREAD_SAFE env variable check
For making the debugging with any deadlocks by the newly introduced
thread-safety feature, add a check with LIBASOUND_THREAD_SAFE
environment variable.  When this variable is set to "0", alsa-lib PCM
forcibly disables the whole thread-safe pthread mutex calls.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2016-07-11 15:25:30 +02:00
Takashi Iwai
54931e5a54 pcm: Add thread-safety to PCM API
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>
2016-07-11 15:25:30 +02:00
Takashi Iwai
c9a0d7d601 conf: Add thread-safe global tree reference
Most of open functions in alsa-lib have the call pattern:
  snd_config_update();
  return snd_xxx_open(x, snd_config, ...);

This means that the toplevel config gets updated, and passed to a
local open function.  Although snd_config_update() itself has a
pthread mutex to be thread safe, the whole procedure above isn't
thread safe.  Namely, the global snd_config tree may be deleted and
recreated at any time while the open function is being processed.
This may lead to a data corruption and crash of the program.

For avoiding the corruption, this patch introduces a refcount to
config tree object.  A few new helper functions are introduced as
well:
- snd_config_update_ref() does update and take the refcount of the
  toplevel tree.   The obtained config tree has to be freed via
  snd_config_unref() below.
- snd_config_ref() and snd_config_unref() manage the refcount of the
  config object.  The latter eventually deletes the object when all
  references are gone.

Along with these additions, the caller of snd_config_update() and
snd_config global tree in alsa-lib are replaced with the new helpers.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2016-05-17 15:51:20 +02:00
Jaroslav Kysela
0f4f48d377 pcm_hw: fix possible memory leak (coverity) 2016-01-12 16:07:16 +01:00
Mike Frysinger
7e90867487 pcm: drop unused sys/shm.h inclusion
This header isn't used in these files, so stop trying to include it.
This helps builds on systems that don't provide the header (such as
Android/Bionic).

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-11-05 14:37:10 +01:00
Martin Geier
77b6be6387 pcm: restore hw params on set latency failed
When method snd_pcm_set_params sets sample rate to 22050 and latency to 50000
to davinci soc driver method snd_pcm_hw_params_set_buffer_time_near fails
and variable params is already changed in the method so the next method
snd_pcm_hw_params_set_period_time_near fails also.

Signed-off-by: Martin Geier <martin.geier@streamunlimited.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-07-24 18:19:37 +02:00
Pierre-Louis Bossart
6ec2464f39 pcm: add support for get/set_audio_htstamp_config
Enable kernel-side functionality by letting user select what sort of
timestamp it desires

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-07-02 17:02:03 +02:00
Pierre-Louis Bossart
6cb31b4444 pcm: add helper functions to query timestamping capabilities
extend support to link, link_estimated and link_synchronized
timestamp. wall-clock is deprecated

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-07-02 17:02:03 +02:00
Takashi Iwai
7d9972c6ad Allow hint for ctl, hwdep, timer and seq
Like pcm and rawmidi, each object parser needs to accept the hint
component.  Now a new local function _snd_conf_generic_id() was
introduced to replace each call of "comment" and "type" field checks.

Also, the two existing identical functions for pcm and rawmidi are
removed and the new function is used commonly.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-04-30 14:52:35 +02:00
Anssi Hannula
b2ed0aa9f2 pcm: fix buffer overflow in snd_pcm_chmap_print()
The size argument is wrong for one of the snprintf() calls in
snd_pcm_chmap_print(), allowing an overflow to happen (the user-provided
buffer may be written data up to 2x its actual size).

Seen in an user report here: http://trac.kodi.tv/ticket/15641

Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2014-12-31 10:02:20 +01:00
Tim Cussins
a649c4b1a0 pcm: Fix assorted tstamp_type bugs/omissions.
Just a couple of quick fixes related to tstamp_type.

- snd_pcm_sw_params(): copy tstamp_type field
- snd_pcm_tstamp_type_name(): fix argument type
- snd_pcm_dump_sw_setup(): fix dumping of tstamp_type field

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2014-11-25 16:34:22 +01:00
Jussi Laako
b14c49ab3d pcm: Fix DSD sample format endianess and add big-endian format
This patch adds big-endian DSD sample format and fixes return value of DSD
formats for snd_pcm_format_little_endian().

Signed-off-by: Jussi Laako <jussi@sonarnerd.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2014-11-21 15:11:05 +01:00
Renu Tyagi
f78ba070b3 pcm: return negative value in case of error
Signed-off-by: renu tyagi <renu.tyagi@samsung.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2014-09-23 09:08:23 +02:00
Jurgen Kramer
e59ffbf30e pcm: add new 32-bit DSD sample format
Add the new DSD_U32_LE sample format to alsa-lib.

NB include/pcm.h and include/sound/asound.h are updated so a new sync with the
kernel headers is not needed

Signed-off-by: Jurgen Kramer <gtmkramer@xs4all.nl>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2014-09-10 09:10:50 +02:00
Takashi Iwai
55c5362521 pcm: Fill sw_params proto field
Fill the new proto field introduced to sw_params with the current PCM
protocol version.  This makes tstamp_type evaluated properly in the
kernel.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2014-07-22 12:14:49 +02:00
Takashi Iwai
0d393c29a2 pcm: Add sw_params API functions to get/set timestamp type
For obtaining / changing the timestamp type, add the corresponding
sw_params accessor API functions together with the public definitions
of timestamp types.

This patch only adds the functions and defines but doesn't bring the
functional changes yet.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2014-07-14 18:12:21 +02:00
Olivier Langlois
3baf1bee84 alsa-lib: minor typo in pcm doc
Added a missing 'f' in the word 'diferent'

Signed-off-by: Olivier Langlois <olivier@trillion01.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
2014-01-06 09:07:11 +01:00
Laurentiu Nicola
d469ebe2ef pcm: Fix a wrong value shown in the error message in rate plugin
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2013-08-08 12:29:09 +02:00
David Henningsson
d20e24e5d1 chmap: Always succeed setting the map to what it already is
If we try to set the channel map to what it already is, this should
always succeed. E g, speaker-test can do this sometimes.

Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2013-06-05 17:56:03 +02:00
Jordi Mallach
3d7433a3c8 pcm: Fix typo in documentation: PREPARE → PREPARED.
Signed-off-by: Jordi Mallach <jordi@debian.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2013-05-23 14:52:04 +02:00
Daniel Mack
886f0cc3c2 bring pcm.h and pcm.c in sync with the kernel list
In particular, this adds definitions and descriptions for G.723 and
DSD types.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2013-04-18 11:45:11 +02:00
Daniel Mack
697f8c296c pcm.c: fix indentation
Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2013-04-18 11:45:01 +02:00
Jaroslav Kysela
e23fb2c4de control, pcm: implement snd_ctl_abort() and snd_pcm_abort() functions
Upon an interrupt, it is necessary to abort the wait loops with the EINTR
error code. Introduce snd_*_abort() functions to handle this case.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
2013-04-08 13:28:03 +02:00
Daniel Svensson
730c833dd8 pcm: fix typo, should be SND_PCM_STATE_PREPARED.
Signed-off-by: Daniel Svensson <dsvensson@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2013-04-05 07:36:28 +02:00
Jaroslav Kysela
009193a345 pcm: fix and optimize snd_pcm_areas_copy function
The memcpy() function in snd_pcm_area_copy() should not be called
with the overlapped areas. Alex discovered - using own LD_PRELOAD checked
for memcpy() input - that the memcpy() is called with src == dst.

For some special plugin combos (rate+softvol+hw for example), the same
areas with same offsets can be asked to be copied (softvol). The collapse
check uses own areas created on heap, causing dst_area == src_area &&
dst_offset == src_offset check bypassed.

Two fixes are in this patch:

- use assert to check the memcpy() input for future triggers
- bypass the snd_pcm_area_copy() call for collapsed identical areas

Reported-by: Alexander Kruppa <akruppa@gmail.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
2013-03-20 20:43:34 +01:00
Takashi Iwai
03c26d0ede PCM: Fix conflict of _snd_pcm_hw_params definitions
Fix the call of _snd_pcm_hw_params() to _snd_pcm_hw_params_internal().
The build passed wrongly because of _snd_pcm_hw_params define.
Having the same function name as the struct name is is simply
confusing...

Also, to be sure, _snd_pcm_hw_params is undef'ed in pcm_local.h, too.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2012-12-04 12:17:00 +01:00
Takashi Iwai
67d692af48 PCM: Add more chmap definitions for UAC2
The new PCM chmap positions have been added in (to be) 3.8-rc1 kernel,
and now updated alsa-lib, too.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2012-11-26 18:10:26 +01:00
Takashi Iwai
9b5beef1dd Merge kernel uapi/sound/asound.h and asequencer.h
Instead of keeping modified asound.h and asequencer.h, copy the files
in the kernel include/uapi/sound as is, and give some renames for
avoiding conflicts with alsa-lib's definitions.

Some structs, unions and typedefs in asound.h and asequencer.h are
once renamed in local.h before inclusion, then renamed back again.

A bonus by this action is that some local codes don't have to refer to
sndrv_xxx any longer.  However, some codes like src/seq/seq.c need
explicit cast because of unavoidable conflicts of struct types.

Another significant change is that now snd_pcm_sw_params.period_event
field is removed.  Instead, try to access the last reserved field
internally.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2012-11-26 18:02:17 +01:00
Takashi Iwai
3fd4ab9be0 PCM: Avoid busy loop in snd_pcm_write_areas() with rate plugin
snd_pcm_write_areas() tries to wait until avail >= avail_min condition
is satisfied.  This doesn't work always well when a rate plugin is in
the play.

When a partial data with a smaller size than a period is written, the
rate plugin doesn't transfer the data immediately to the slave PCM,
but kept in an internal buffer and it changes only the hwptr of the
plugin.  Thus, the condition "avail < avail_min" is triggered for a
wait check although the underlying slave PCM has enough room.  This
results in a call of snd_pcm_wait() which returns immediately after
poll() call, and the snd_pcm_write_areas() loop continues.  As a
consequence, it falls into a CPU hog.

This patch fixes that busy loop by introducing a new fast_ops to check
the availability for wait of avail_min.  Then a plugin can ask the
slave PCM whether the wait is required (or possible).

A few plugins like multi plugin need a special handling.  Otherwise a
generic plugin function can be used.

Reported-by: Trent Piepho <tpiepho@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2012-11-13 16:16:26 +01:00
Jaroslav Kysela
edcd677bf2 PCM: Fix memory leak for pcm empty and asym plugins
The init-only plugins do not have own pcm handle, so free the references
to open function immediately after open.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
2012-10-30 11:43:07 +01:00
Pierre-Louis Bossart
cf40ea169a pcm: support for audio timestamps
add new snd_pcm_status_get_audio_htstamp() routine to
query the audio timestamps provided by the kernel.

This change provides applications with better ways
to track elapsed time. Before this patch, applications
would subtract queued samples (delay) from written samples,
resulting in a 1-2 sample error.

Also add snd_pcm_hw_params_supports_audio_wallclock_ts()
to query what the hardware supports.

TODO: check protocol compatibility?

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2012-10-25 00:13:51 +02:00
Takashi Iwai
63f6f4a610 PCM: A few doxygen fixes for chmap stuff
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2012-09-13 08:38:59 +02:00
Takashi Iwai
c6db60e327 PCM: Fix the conversion from string to chmap position
Use strncasecmp() to allow lower cases, and also evaluate the inverted
phase suffix, too.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2012-09-13 08:24:59 +02:00
Takashi Iwai
f7300682dc PCM: Define MONO and other channel map positions
Follow the new definitions in the kernel side.  MONO and others have
been added, and the order of position table was changed again.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2012-09-13 08:24:59 +02:00
Takashi Iwai
ec7acfc408 PCM: Use compounds for overriding / enhancing chmaps
Instead of a single channel map, multiple channel maps can be provided
in a form of compound (array) to hw and null plugins.  In null
get_chmap, the channel map corresponding to the current channels is
copied from the given channel maps.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2012-09-13 08:24:59 +02:00