Rosen Penev [Wed, 20 Nov 2019 19:13:55 +0000 (11:13 -0800)]
aplay: Limit VUMeter progress bar to 100 for negative as well
While the progress bar cannot be negative, GCC concludes that it can be
and assumes tmp can be written past the end. Fixes this GCC warning:
aplay.c:1747:18: warning: '%02d' directive writing between 2 and 11 bytes
into a region of size 4 [-Wformat-overflow=]
1747 | sprintf(tmp, "%02d%%", maxperc[c]);
Rosen Penev [Wed, 20 Nov 2019 18:19:20 +0000 (10:19 -0800)]
aplay: Adjust buffer sizes to fix snprintf warnings
It also reduces compiled size slightly.
aplay.c: In function 'capture':
aplay.c:3055:34: error: '-01' directive output may be truncated writing 3
bytes into a region of size between 1 and 4097 [-Werror=format-truncation=
]
3055 | snprintf(namebuf, namelen, "%s-01", buf);
| ^~~
aplay.c:3055:4: note: 'snprintf' output between 4 and 4100 bytes into a
destination of size 4097
3055 | snprintf(namebuf, namelen, "%s-01", buf);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
aplay.c:3053:34: error: '-01.' directive output may be truncated writing 4
bytes into a region of size between 1 and 4097 [-Werror=format-truncation=
]
3053 | snprintf(namebuf, namelen, "%s-01.%s", buf, s);
| ^~~~
aplay.c:3053:4: note: 'snprintf' output 5 or more bytes (assuming 4101)
into a destination of size 4097
3053 | snprintf(namebuf, namelen, "%s-01.%s", buf, s);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
aplay.c:3065:34: error: '%02i' directive output may be truncated writing
between 2 and 10 bytes into a region of size between 0 and 4096 [-Werror=
format-truncation=]
3065 | snprintf(namebuf, namelen, "%s-%02i", buf, filecount);
| ^~~~
aplay.c:3065:30: note: directive argument in the range [1, 2147483647]
3065 | snprintf(namebuf, namelen, "%s-%02i", buf, filecount);
| ^~~~~~~~~
aplay.c:3065:3: note: 'snprintf' output between 4 and 4108 bytes into a
destination of size 4097
3065 | snprintf(namebuf, namelen, "%s-%02i", buf, filecount);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
aplay.c:3063:34: error: '%02i' directive output may be truncated writing
between 2 and 10 bytes into a region of size between 0 and 4096 [-Werror=
format-truncation=]
3063 | snprintf(namebuf, namelen, "%s-%02i.%s", buf, filecount, s);
| ^~~~
aplay.c:3063:30: note: directive argument in the range [1, 2147483647]
3063 | snprintf(namebuf, namelen, "%s-%02i.%s", buf, filecount, s);
| ^~~~~~~~~~~~
aplay.c:3063:3: note: 'snprintf' output 5 or more bytes (assuming 4109)
into a destination of size 4097
3063 | snprintf(namebuf, namelen, "%s-%02i.%s", buf, filecount, s);
Takashi Sakamoto [Tue, 29 Oct 2019 15:13:39 +0000 (00:13 +0900)]
axfer: handle -ETIMEDOUT before non-block I/O operation
When running for IRQ-based scheduling model, transmission backend is
expected to queue PCM event in different context from the main thread.
When queueing no events during time equivalent to one period of PCM
buffer, the backend has problems.
This commit outputs report it for non-blocking operation for IRQ-based
scheduling model. The timeout is equivalent to all frames in buffer,
instead of period for safe.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Takashi Sakamoto [Tue, 29 Oct 2019 15:14:14 +0000 (00:14 +0900)]
axfer: handle -ETIMEDOUT before handle mmap I/O operation
When running for IRQ-based scheduling model, transmission backend is
expected to queue PCM event in different context from the main thread.
When queueing no events during time equivalent to one period of PCM
buffer, the backend has problems.
This commit outputs report it for mmap operation for IRQ-based
scheduling model. The timeout is equivalent to all frames in buffer,
instead of period for safe.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Takashi Sakamoto [Wed, 30 Oct 2019 01:10:54 +0000 (10:10 +0900)]
axfer: fix to return error code when a call of select(2) fails
A call of select(2) returns negative code and report errors via errno
local variable, howver current waiter implementation for select(2)
returns the negative code instead of errno.
This commit fixes it.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Takashi Sakamoto [Tue, 29 Oct 2019 15:07:59 +0000 (00:07 +0900)]
axfer: return the number of file descriptors for I/O events from select(2) waiter
A call of select(2) returns error code at failure, the number of file
descriptors available I/O at success. Current implementation of
waiter abstraction for select(2) returns 0 at success and callers
can't get the number.
This commit fixes it.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Jaroslav Kysela <perex@perex.cz>
chunxu.li [Sun, 23 Jun 2019 15:54:29 +0000 (23:54 +0800)]
aplay: fix memory leak when setup_chmap() fail
setup_chmap() will return with error number if hw_map calloc fail or
channels doesn't match with hw_params, but memory free was ignored when
error occurs.
Each container should be configured to store one saple per frame in
demuxer case. This commit fixes the bug.
Fixes: 25c8e3bebb53 ('axfer: add support for a mapper for multiple target') Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit fixes uninitialized return value from a call of test_mux() and
text_demux() to suppress warnings below:
$ make check
...
gcc -DHAVE_CONFIG_H -I. -I../../include -O2 -Wall -pipe -g -MT mapper-test.o -MD -MP -MF .deps/mapper-test.Tpo -c -o mapper-test.o mapper-test.c
mapper-test.c: In function ‘test_mapper’:
mapper-test.c:241:9: warning: ‘err’ may be used uninitialized in this function [-Wmaybe-uninitialized]
return err;
^~~
mapper-test.c:231:5: warning: ‘err’ may be used uninitialized in this function [-Wmaybe-uninitialized]
if (err < 0)
^
Fixes: 39d1ab8a0cb4: ('axfer: add a unit test for mapper interface') Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Jaroslav Kysela <perex@perex.cz>
This commit fixes uninitialized return value from a call of test_vector()
to suppress a warning below.
gcc -DHAVE_CONFIG_H -I. -I../../include -O2 -Wall -pipe -g -MT mapper-test.o -MD -MP -MF .deps/mapper-test.Tpo -c -o mapper-test.o mapper-test.c
mapper-test.c: In function ‘test_vector’:
mapper-test.c:293:6: warning: ‘err’ may be used uninitialized in this function [-Wmaybe-uninitialized]
int err;
^~~
Fixes: 39d1ab8a0cb4: ('axfer: add a unit test for mapper interface') Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Samuel Holland [Sun, 21 Apr 2019 00:13:20 +0000 (19:13 -0500)]
axfer: Declare global variables as 'extern' in header
This avoids multiple definitions of the same global variable (one in
each file that includes this header), and fixes a linking error when
compiled with -fno-common.
Fixes: 96110793b3e5 ("axfer: add support for a container of raw data") Signed-off-by: Samuel Holland <samuel@sholland.org> Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Samuel Holland [Sun, 21 Apr 2019 00:15:54 +0000 (19:15 -0500)]
axfer: Fix creation of v1.2 headers on big-endian systems
struct block_v120_format defines these members as uint8_t. On
little-endian systems, no swapping is done, and the generated block
header is fine. However, on big-endian machines, the value is swapped to
the high byte and then truncated by the assignment, causing both
bits_per_sample and samples_per_frame to be zero.
This fixes an assertion failure in container-test when later
parsing the header ["assert(*samples_per_frame > 0);" in
container_context_pre_process()].
Fixes: 4ab7510f3a18: ("axfer: add support for a container of Creative Tech. voice format") Signed-off-by: Samuel Holland <samuel@sholland.org> Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Get rid of a warning about implicit declaration of exp10, which is
behind _GNU_SOURCE as a non-standard feature. The same problem was fixed
for alsamixer in commit 116488e5f2f1b897084bd151381ee254e1cc177d.
Prashant Malani [Tue, 29 Jan 2019 09:58:26 +0000 (01:58 -0800)]
seq: arecordmidi: Add num-events option
Add a command line option to automatically exit after recording a fixed
number of MIDI events. This allows a program using arecordmidi to expect
a MIDI file to be written automatically when the specified number of
events have been received, instead of having to send a SIGINT or SIGTERM
programmatically.
It also avoids the need to have the arecordmidi process running in the
background, and then constantly stat the output file to check if any
bytes have been written to it (this makes for less predictable and
longer-running tests).
This functionality finds use in Chrome OS functional testing, since
having to send SIGTERM/SIGINT programmatically and then wait for the
output file adds unpredictability and delay to the tests.
The addition of this command-line option should (hopefully) not break
any existing usage.
Takashi Sakamoto [Sun, 27 Jan 2019 02:24:53 +0000 (11:24 +0900)]
axfer: add missing header file of unit test to distribution
The file 'axfer/test/generator.h' is missing in distribution and brings
FTBFS for unit tests of axfer.
This commit fixes to add it.
Reported-by: Elimar Riesebieter <riesebie@lxtec.de> Fixes: b878df1ff0b0: ('axfer: add unit test for container interface') Fixes: 39d1ab8a0cb4: ('axfer: add a unit test for mapper interface') Signed-off-by: Takashi Iwai <tiwai@suse.de>
Takashi Sakamoto [Sun, 27 Jan 2019 08:36:22 +0000 (17:36 +0900)]
axfer: allow to be compiled with glibc-2.11 or former
The program, axfer, was developed in userspace with glibc-2.28. This
userspace is mostly compliant to POSIX:2008 and some additional macros
for poll event are officially available. The glibc supports them as a
default since its v2.12 release. It will be failed to be compiled with
old glibc or the other libraries for C standard APIs.
One of the purpose of axfer is an better alternative of aplay. In a
point of the purpose, it's preferable to be compiled with the old
libraries.
This commit adds conditional macros to be compiled with libraries for
old compliance level of POSIX.
Reported-by: Jay Foster <jay@systech.com> Fixes: fce16d9279b6 ('axfer: add an implementation of waiter for select(2)') Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Takashi Sakamoto [Sun, 27 Jan 2019 05:48:33 +0000 (14:48 +0900)]
axfer: correct description about snoop mode of libffado
The libffado library can listen to isochronous channels to which unit on
IEEE 1394 bus transfers packets as long as the unit allows software to
read the channel from its register.
This commit corrects description about snoop mode.
Jaroslav Kysela [Fri, 18 Jan 2019 08:24:12 +0000 (09:24 +0100)]
alsamixer: define _GNU_SOURCE to get exp10
Fixes Master, Headphones and Speaker stuck at -8 percentage after
building with Clang 7.0.1 and getting warned about implicit declaration
of exp10, which is behind _GNU_SOURCE as a non-standard feature. Thanks
Takashi Iwai for the CFLAGS suggestion on the mailing list. GCC build is
not affected, so not adding a compiler check to the configure script.
uClibc-ng has got exp10 since 1.0.12, so the fallback macro is no longer
needed. However, alsa-utils relies on gettext so might need further
patches to actually work on uClibc systems.
Signed-off-by: makepost <makepost@firemail.cc> Signed-off-by: Jaroslav Kysela <perex@perex.cz>
axfer: add an explanation about advantages/issues of Timer-based scheduling model
Timer-based scheduling model has some merits against IRQ-based
scheduling model. However, as of Linux kernel v4.21, ALSA PCM interface
between kernel/userspace has a lack of some features.
axfer: add an explanation about Timer-based scheduling model
This commit fulfills a subsection titled as 'Timer-based scheduling model'.
This scheduling model is introduced in a recent decade. In this model,
applications should take care of its timing to operate sampled data
according to any timer. This is an optional behaviour of runtime of
PCM substream.
axfer: add an explanation about IRQ-based scheduling model
This commit adds a section titled as 'SCHEDULING MODEL' and fulfill a
subsection titled as 'IRQ-based scheduling model'.
This scheduling model is for a typical applications to operate a kind of
data sampled against actual time. In this model, ALSA PCM core maintains
timing of the applications with notification of hardware by
blocking/waking up their processes. This is a default behaviour of
runtime of PCM substream.
Takashi Sakamoto [Fri, 21 Dec 2018 11:48:44 +0000 (20:48 +0900)]
axfer: add text for compatibility loss of sw parameter in libasound backend
At present, some options for software parameters have actual effects in
cases neither mmap operation nor timer-based scheduling model is used.
For mmap operation, backward compatibility to aplay(1) is lost.
Takashi Sakamoto [Mon, 17 Dec 2018 06:51:03 +0000 (15:51 +0900)]
axfer: print help for libasound backend
This commit attempts to categorise existing options to four parts;
basics, software features, libasound plugin options and debug assistant.
These categories will assist users to get purpose of each option.
Takashi Sakamoto [Fri, 21 Dec 2018 05:16:24 +0000 (14:16 +0900)]
axfer: fulfill manual section for libffado backend
I note that libffado backend has no support for suspend/resume because
libffado has enough implementation for these features even if it exports
some symbols for them. For this backend, reception of signals for the
features brings abortion of runtime.
Takashi Sakamoto [Mon, 17 Dec 2018 05:07:27 +0000 (14:07 +0900)]
axfer: fix no return statement in print_help() function
A function, print_help() in xfer module is defined to return integer
value, however this is useledd.
This commit fixes it.
Fixes: 908ff69be246 ('axfer: print help text of transfer subcommand just for common options') Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit adds help text of command entry. This is printed when
help subcommand is given, or a valid subcommand or a valid direction
are not given.
Unfortunately, at present, execution of alias (aplay/arecord) with help
options prints the added help text. It should print help options in
transfer subcommand. This bug will fixed in future commits.
axfer: add a section about design of transfer subcommand
An implementation of transfer subcommand is the most large part and
complicated somehow. This commit adds a section titled 'DESIGN' to
manual to overall design of the subcommand.
This commit adds a manual for transfer subcommand in axfer(1). This
subcommand is a main feature of this command, to transfer audio data
frame between device/node and file/stdio.
This subcommand is designed to have several transmission backend.
Detail explanation about these backends is added in future commits.
This commit adds a manual for list subcommand of axfer(1). At present,
this subcommand prints helpful information to transfer subcommand in
libasound backend.
This commit adds a manual for axfer(1). This command is an entry point
to supported subcommand.
I note that axfer(1) has renewed option system against aplay(1). The
command get positional two options for subcommand and direction. In
short:
$ axfer transfer capture|playback [options for transfer subcommand]
$ axfer list capture|playback [options for list subcommand]
$ axfer version
$ axfer help
Manuals to subcommands are added later separately.
axfer: check whether a terminal is referred for stdio
A reference to a terminal for standard input/output brings some
troubles. For capture transmission, it can bring some terminal
control codes and it's possible to make the terminal in disorder.
For playback transmission, it can bring endless loop to read
data for detection of type of container.
This commit checks whether a terminal is referred for the standard
input/output by a call isatty(3). When detecting a terminal,
axfer run time prints message and goes to finish.
axfer: truncate parsed arguments before operating subcommand
When subcommands are operated, top-most two arguments are already
parsed in renewed command system, thus they're useless. Besides,
they're possible to be parsed by getopt_long(3).
This commit truncates these options before entering subcommand
operation.
axfer: use transfer subcommand as a default for compatibility mode to aplay(1)
At present, both of help and transfer subcommands are used when options
are missing in compatibility mode to aplay(1). However, in a view of
users, it should be transfer subcommand.
This commit uses transfer subcommand as a default for the mode.
axfer: use second argument in command line for transmission direction
In renewed command system, axfer uses first argument for subcommand. In
popular subcommand such as transfer, transmission direction is required.
At present, some options in aplay(1) are used for this purpose however
it's understandable to use second argument for this purpose.
This commit uses second argument as fixed position to indicate
direction for renewed command system.
Takashi Sakamoto [Tue, 13 Nov 2018 06:41:47 +0000 (15:41 +0900)]
axfer: add support for libffado transmission backend
At present, axfer is designed to use several types of backend for
transmission of data frames. This commit is an implementation
example of the backend.
Libffado is a userspace library for transmission of data frames according
to protocols similar to IEC 61883-1/6. This library handles audio and
music units on IEEE 1394 bus.
Unfortunately, this library executes ctor/dtor of instances for some
objects in startup/finish routines of C runtime. As a result, it outputs
some superfluous messages even if the backend is not actually used.
Furthermore, this library brings memory leak internally. Therefore,
it's not practical to build this backend for generic purposes. Although
the backend implementation works fine, this commit is just for technical
preview.
Takashi Sakamoto [Tue, 13 Nov 2018 06:41:46 +0000 (15:41 +0900)]
axfer: obsolete some unimplemented options
Althogh many options are actually supported by aplay, some of them are
not enough good in practical points. For example, '--test-position'
option is meaningless for some use cases. Furthermore, due to practical
reasons, some options are not implemented well; e.g. vumeter.
Takashi Sakamoto [Tue, 13 Nov 2018 06:41:45 +0000 (15:41 +0900)]
axfer: add support for timer-based scheduling model with MMAP operation
In 2010, ALSA PCM interface got an flag of hardware parameters to suppress
periodical interrupts, according to a request from PulseAudio developer.
In typical PCM operation for usual hardware, PCM drivers configure the
hardware to generate the periodical interrupts to notify that the same
amount of data frames as a period of PCM buffer is actually transferred
via serial sound interface. The flag can suppress this if the driver
support it.
There's some merits of this configuration:
- No interrupt context run for PCM substream. The PCM substream is
handled in any process context only. No need to care of race
conditions between interrupt/process contexts. This is good for
developers of drivers and applications.
- CPU time is not used for handlers on the interrupt context. The CPU
time can be dedicated for the other tasks. This is good in a point
of Time Sharing System.
- Hardware is not configured to generate interrupts. This is good in a
point of reduction of overall power consumption.
Disabling period interrupt is used for 'Timer-based scheduling' to
consume data frames on PCM buffer independently of interrupt context. As
noted, no interrupt context runs for PCM substream, thus any blocking
operation is not released. Furthermore, system calls for multiplexed I/O
is not also released without timeout.
In this scheduling model, applications need to care of available space on
PCM buffer by lapse of time, typically by yielding CPU and wait for
rescheduling. For the yielding, timeout is calculated for preferable
amount of PCM frames to process. This is an additional merit for
applications, like sound servers. when an I/O thread of the server wait
for the timeout, the other threads can process data frames for server
clients. Furthermore, with usage of rewinding/forwarding, applications
can achieve low latency between transmission position and handling
position even if they uses large size of PCM buffers.
But the timeout should be calculated with enough care of hardware
capabilities. To disable period interrupt, used hardware should satisfy
some requirements for data transmission:
1. Even if drivers don't handle interrupts to queue next data transmission,
hardware voluntarily perform the data transmission when needed
(typically by requesting DMA automatically).
2. hardware has a capability to report current position of data
transmission with enough accuracy against the data transmission.
developers refer this as 'granularity'. If hardware can always
reports updated position after the data transmission finishes, the
granularity equals to the size of period of PCM buffer.
3. a fine size of data transmission in one time. This size is decided
depending on configuration of hardware or DMA controller, but for
efficiency it may not be one byte. Thus some amount of data frame is
transferred by one data transmission. Developers refer this as
'burst-ness'.
The timeout should be calculated according to the item 2 and 3, however
in current ALSA PCM interface supplemental information is not delivered
from drivers to applications. Although at present userspace applications
should be written by a speculative way for this point, there's few
problems because there're a few hardware which satisfy the above items.
However, when more drivers supports this feature, the problem may largely
be exposed and bothers application developers.
This commit adds an option to use 'timer-based scheduling' for data
transmission. This commit adds '--sched-model' option, and the scheduling
mode is enabled when 'timer' is assigned to the option by equal sign.
Although there's some TODOs, you can see the scheduling mode in this
simple program, like:
$ axfer transfer --sched-model=timer -P -d 2 -D hw:0,3 /dev/urandom -f dat -vvv
$ axfer transfer --sched-model=timer -C -d 2 -D hw:1,0 /dev/null -r 48000 -vvv
Takashi Sakamoto [Tue, 13 Nov 2018 06:41:44 +0000 (15:41 +0900)]
axfer: add an implementation of waiter for epoll(7)
This commit adds support of waiter for Linux specific epoll(7) system call.
For portability to the other Unix-like systems such as xBSD, modification
of Makefile.am may be required for conditional build, but this commit
includes no changes for it.
Below lines are examples to use this option:
$ axfer transfer --waiter-type=epoll -M -P -d 2 -D hw:0,3 /dev/urandom -f dat -vvv
$ axfer transfer --waiter-type=epoll -M -C -d 2 -D hw:1,0 /dev/null -r 48000 -vvv
Takashi Sakamoto [Tue, 13 Nov 2018 06:41:41 +0000 (15:41 +0900)]
axfer: add an option for waiter type
This commit is an integration to add an option for users to choose waiter
type. Users give the type to value to '--waiter-type' ('-w') option to
choose it. Currently, 'snd_pcm_wait()' is just supported as a default.
This alsa-lib API is implemented with a call of poll(2).
Takashi Sakamoto [Tue, 13 Nov 2018 06:41:40 +0000 (15:41 +0900)]
axfer: add a common interface of waiter for I/O event notification
There're several types of system calls for multiplexed I/O. They're used to
receive notifications of I/O events. Typically, userspace applications call
them against file descriptor to yield CPU. When I/O is enabled on any of
the descriptors, a task of the application is rescheduled, then the
application execute I/O calls.
This commit adds a common interface for this type of system calls, named as
'waiter'. This is expected to be used with non-blocking file operation and
operations on mapped page frame.
Takashi Sakamoto [Tue, 13 Nov 2018 06:41:39 +0000 (15:41 +0900)]
axfer: add options for plugins in alsa-lib
As of 2017, two userspace library implementations are known; alsa-lib and
tinyalsa. The latter is simple I/O library to use ALSA PCM interface. On
the other hand, alsa-lib is more complicated than it. This is because it's
designed to add features to transmission of data frames; e.g. sample
resampling. To achieve this, alsa-lib has its configuration space and
plugin system.
In aplay, some options are implemented as a flag for the plugins in
alsa-lib. The flag is given to snd_pcm_open(). This commit adds support
for the flags.
Takashi Sakamoto [Tue, 13 Nov 2018 06:41:38 +0000 (15:41 +0900)]
axfer: add options for software parameters of PCM substream
In ALSA PCM interface, some parameters are used to configure runtime of
PCM substream independently of actual hardware. These parameters are
mainly used to decide the detailed timing to start/stop PCM substream and
release I/O blocking state of application. These parameters are
represented and delivered by a structure.
In alsa-lib PCM API, the structure is hidden from userspace applications.
The applications can set/get actual parameters by helper functions.
In aplay, three of the parameters are configurable. This commit adds
support for them. When no options are given, default values are used.
Takashi Sakamoto [Tue, 13 Nov 2018 06:41:37 +0000 (15:41 +0900)]
axfer: add options for buffer arrangement
In ALSA PCM interface, two parameters are used for size of intermediate
buffer for data frames; period size and buffer size. Actual effects of
these sizes differs depending on hardware, but basically the size of
period is used for intervals of hardware interrupts and the size of buffer
is used to maintain the intermediate buffer as ring buffer. These
parameters can be configured as a part of hardware parameters by
data frame unit or micro second. PCM API in alsa-lib also includes
helper functions to configure them by the two units.
This commit adds support for options to the parameters by both units. When
no options are given, default values are applied according to current
aplay; available maximum size of buffer up to 500msec, a quarter of the
size of buffer for period size. However, these calculation should be
reconsidered somehow.
Takashi Sakamoto [Tue, 13 Nov 2018 06:41:36 +0000 (15:41 +0900)]
axfer: add an option to suppress event waiting
In aplay, '--test-nowait' is used to suppress calls of snd_pcm_wait()
when I/O operations return -EAGAIN or process truncated number of data
frames. This seems to be for debugging purpose. In this program, this
option is equivalent to suppress event waiting.
git://git.alsa-project.org / alsa-utils.git / log