This patch allows the effective period size to be a multiple of the
slave-pcm period size.
Allowing only exact multiple of original period size is achieved by
borrowing code from the kernel hwrules implementation.
This patch is intended to save cpu workload when for example, the
slave operates with very small periods but a user does not need that
small periods.
This feature is enabled by default and can be disabled by adding
config option 'var_periodsize 0'.
Signed-off-by: Alexander Jahn <ajahn@de.adit-jv.com>
Signed-off-by: Andreas Pape <apape@de.adit-jv.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
In the case of dshare, dsnoop, and dmix when a device is opened twice
and fails the second time, the semaphore is completely discarded. This
creates dangling semaphore data.
This patch removes the possibility for the semaphore to be destroyed during
a typical open failure by first checking if the shared memory can be destroyed
or not. If the shared memory cannot be released it means both it and the
semaphore are still in use and therefore the semaphore is just released.
Signed-off-by: Joshua Frkuska <joshua_frkuska@mentor.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>
The commit [fdba9e1bad: pcm: Fallback open as the first instance for
dmix & co] introduced a mechanism to retry the open of slave PCM for
the secondary streams, but this also introduced a regression in dsnoop
and dshare plugins: since the retry goto-tag was placed at a wrong
position, it retries to re-fetch the shm unnecessarily and eventually
leads to the fatal error.
The bug can be easily reproduced by starting arecord and killing it
via SIGKILL, then starting arecord again. The second arecord fails.
The fix is obviously to move the wrong retry goto-tags to the right
positions.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
dmix and other PCM plugins tries to open a secondary stream with
O_APPEND flag when the shmem was already attached by another.
However, when another streams have been already closed after the
shmem check, this open may return the error EBADFD, since the kernel
accepts O_APPEND only for the secondary streams.
This patch adds a workaround for such a case. It just retries opening
the stream as the first instance (i.e. without O_APPEND flag).
This is basically safe behavior (the kernel takes care of races), even
we may do this even unconditionally. But it's bad from the
performance POV, so we do it only when really needed.
Reported-by: Lars Lindqvist <lars.lindqvist@yandex.ru>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Currently, dmix & co plugins ignore the XRUN state of the slave PCM.
It's (supposedly) because dmix deals with the PCM in a free-wheel
mode, which is equivalent with XRUN. But, this difference (whether
the correct freewheel or XRUN) should be done by the kernel, and we
may have an XRUN state indeed (e.g. via xrun injection).
This patch fixes this lack of behavior, to handle PCM xrun and does
prepare when the slave PCM is in such a state.
Also, the patch consolidates the prepare callback for all dmix, dsnoop
and dshare plugins, and fix/cleanup a bit for dshare/dsnoop codes to
align with dsnoop code.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Fetch the timestamp and other status fields by issuing
snd_pcm_status() for the slave PCM. Also, fill the delay field
properly. This should fix longstanding PA's complaints.
Reported-by: Dan Hordern <danhordern@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
The current behavior of snd_pcm_rewindable and snd_pcm_forwardable means
that the returned value is only accurate to one period. Or maybe even
meaningless if period interrupts are off. Fetch the up-to-date position
of the hardware pointer, as that's what is wanted by callers.
Signed-off-by: Alexander E. Patrakov <patrakov@gmail.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
There are a few places where the argument of the .rewind or .forward
callback is checked against the same value as returned by .rewindable or
.forwardable. Express this "don't rewind more than rewindable" logic
explicitly, so that the future fixes to the rewindable size can go to
one function instead of two.
While at it, take advantage of the fact that snd_pcm_mmap_avail() cannot
return negative values (except due to integer overflow, which is AFAICS
impossible given the current boundary choice).
Signed-off-by: Alexander E. Patrakov <patrakov@gmail.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Now all PCM plugins do support the proper timestamp type or pass it
over slaves. The internal monotonic flag is dropped and replaced with
tstamp_type in all places.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
As reported dead-lock, do local lock counting and invoke abort() when
the lock counts do not match at close() time.
Reported-by: <mateen abdulmateen.shaikh@gmail.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Added new channel-mapping API functions.
Not all plugins are covered, especially the route, multi and external
plugins don't work yet.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Add SETUP state checks and do modifications according latest ALSA driver
(passing wrong event identification).
ALSA bug#4914
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
This ensures they are emitted in .data.rel.ro rather than .data.rel,
which should make a nice difference when using prelink.
Signed-off-by: Diego E. 'Flameeyes' Pettenò <flameeyes@gmail.com>
PCM direct plugins didn't update the timestamp properly.
Now it always starts the slave PCM with MMAP tstamp_mode so that the
timestamp will be being updated. When a client is set up as MMAP
tstamp_mode as well, simply copy this slave timestamp. Otherwise
status callback calculates the current timestamp as usual.
Instead of link_fd, more generic callback link_slaves is introduced.
This is called for linking the slave streams as the source to the
given master stream.
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.
With the patch, dmix allows apps to use more flexible buffer sizes.
The max buffer size is unlimited, and the minimal buffer size is
(period size * 2). The buffer size is aligned to period size.
The period size is still bound to the period size of slave PCM.
To back to the old behavior (the fixed buffer size), you can set
defaults.pcm.dmix_variable_buffer false
in your configuration.
- Support multi-card/device for dmix/dsnoop/dshare plugins
The unique ipc key is calculated based on card/device/sub index
- Clean up and share the code among all d* plugins
- Refer the defaults.pcm.* configuration
The base ipc_key number, ipc_gid and ipc_perm are referred.
- this patch adds support for suspend & result for dmix and other
direct plugins
- the timer detection / initialization (TREAD support) was redesigned and
the check for proper driver version was moved to the timer_hw.c
- Fixed unbalanced semaphores (which may cause deadlock)
- Do semaphore-up before blocking calls for communication with the server
- Don't discard semaphores on the client side
- Open slave PCMs always in non-blocking mode to avoid blocking by semaphore
with the secondary open
