| Age | Commit message (Collapse) | Author | Files | Lines |
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ALSA control core handles ELEM_READ/ELEM_WRITE requests within lock
acquisition of a counting semaphore. The lock is acquired in helper
functions in the end of call path before calling implementations of each
driver.
ioctl(2) with SNDRV_CTL_ELEM_READ
...
->snd_ctl_ioctl()
->snd_ctl_elem_read_user()
->snd_ctl_elem_read()
->down_read(controls_rwsem)
->snd_ctl_find_id()
->struct snd_kcontrol.get()
->up_read(controls_rwsem)
ioctl(2) with SNDRV_CTL_ELEM_WRITE
...
->snd_ctl_ioctl()
->snd_ctl_elem_write_user()
->snd_ctl_elem_write()
->down_read(controls_rwsem)
->snd_ctl_find_id()
->struct snd_kcontrol.put()
->up_read(controls_rwsem)
This commit moves the lock acquisition to middle of the call graph to
simplify the helper functions. As a result:
ioctl(2) with SNDRV_CTL_ELEM_READ
...
->snd_ctl_ioctl()
->snd_ctl_elem_read_user()
->down_read(controls_rwsem)
->snd_ctl_elem_read()
->snd_ctl_find_id()
->struct snd_kcontrol.get()
->up_read(controls_rwsem)
ioctl(2) with SNDRV_CTL_ELEM_WRITE
...
->snd_ctl_ioctl()
->snd_ctl_elem_write_user()
->down_read(controls_rwsem)
->snd_ctl_elem_write()
->snd_ctl_find_id()
->struct snd_kcontrol.put()
->up_read(controls_rwsem)
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Any control event is queued by a call of snd_ctl_notify(). This function
adds the event to each queue of opened file data corresponding to ALSA
control character devices. This function acquired two types of lock; a
counting semaphore for a list of the opened file data and a spinlock for
card data opened by the file. Typically, this function is called after
acquiring a counting semaphore for a list of elements in the card data.
In current implementation of a handler for ELEM_WRITE request, the
function is called after releasing the semaphore for a list of elements
in the card data. This release is not necessarily needed.
This commit removes the release to call the function within the critical
section so that later commits are simple.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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commit 4842e98f26dd80be3623c4714a244ba52ea096a8 ("ALSA: seq: Fix race at
creating a queue") attempted to fix a race reported by syzkaller. That
fix has been described as follows:
"
When a sequencer queue is created in snd_seq_queue_alloc(),it adds the
new queue element to the public list before referencing it. Thus the
queue might be deleted before the call of snd_seq_queue_use(), and it
results in the use-after-free error, as spotted by syzkaller.
The fix is to reference the queue object at the right time.
"
Even with that fix in place, syzkaller reported a use-after-free error.
It specifically pointed to the last instruction "return q->queue" in
snd_seq_queue_alloc(). The pointer q is being used after kfree() has
been called on it.
It turned out that there is still a small window where a race can
happen. The window opens at
snd_seq_ioctl_create_queue()->snd_seq_queue_alloc()->queue_list_add()
and closes at
snd_seq_ioctl_create_queue()->queueptr()->snd_use_lock_use(). Between
these two calls, a different thread could delete the queue and possibly
re-create a different queue in the same location in queue_list.
This change prevents this situation by calling snd_use_lock_use() from
snd_seq_queue_alloc() prior to calling queue_list_add(). It is then the
caller's responsibility to call snd_use_lock_free(&q->use_lock).
Fixes: 4842e98f26dd ("ALSA: seq: Fix race at creating a queue")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Daniel Mentz <danielmentz@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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The commit 0181307abc1d ("ALSA: seq: Reorganize kconfig and build")
rewrote the dependency of each sequencer module in a standard way, but
there was one change applied mistakenly: CONFIG_SND_SEQ_MIDI isn't
enabled properly by CONFIG_SND_RAWMIDI. I seem to have changed the
wrong one instead, CONFIG_SND_SEQ_MIDI_EMUL, which is eventually
reverse-selected by CONFIG_SND_SEQ_MIDI itself. This ended up the
lack of snd-seq-midi module as reported below.
The fix is to put def_tristate properly to CONFIG_SND_SEQ_MIDI instead
of *_MIDI_EMUL entry.
Fixes: 0181307abc1d ("ALSA: seq: Reorganize kconfig and build")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=196633
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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User-defined element set registers own handler to get callbacks from TLV
ioctl handler. In the handler, execution path bifurcates depending on
requests from user space. At write request, container in given buffer is
registered to the element set, or replaced old TLV data. At the read
request, the registered data is copied to user space. The command request
is not allowed. In current implementation, function of the handler
includes codes for the two cases.
This commit adds two helper functions for these cases so that readers can
easily get the above design.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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In a design of ALSA control core, execution path bifurcates depending on
target element. When a set with the target element has a handler, it's
called. Else, registered buffer is copied to user space. These two
operations are apparently different. In current implementation, they're
on the same function with a condition statement. This makes it a bit hard
to understand conditions of each case.
This commit splits codes for these two cases.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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At a previous commit, concurrent requests for TLV data are maintained
exclusively between read requests and write/command requests. TLV
callback handlers in each driver has no risk from concurrent access for
reference/change.
In current implementation, 'struct snd_card' has a mutex to control
concurrent accesses to user-defined element sets. This commit obsoletes it.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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In ALSA control interface, applications can execute three types of request
for Type-Length-Value (TLV) data to a set of elements; read, write and
command. In ALSA control core, all of the requests are handled within read
lock to a counting semaphore, therefore several processes can run to access
to the data at the same time for any purposes. This has an issue because
write and command requests have side effect to change state of a set of
elements for the TLV data. Concurrent access should be controlled for each
of reference/change case.
This commit uses the counting semaphore as read lock for TLV read requests,
while use it as write lock for TLV write/command requests. The state of a
set of elements for the TLV data is maintained exclusively between read
requests and write/command requests, or between write and command requests.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Any control event is queued by a call of snd_ctl_notify(). This function
adds the event to each queue of opened file data corresponding to ALSA
control character devices. This function acquired two types of lock; a
counting semaphore for a list of the opened file data and a spinlock for
card data opened by the file. Typically, this function is called after
acquiring a counting semaphore for a list of elements in the card data.
In current implementation of TLV request handler, the function is called
after releasing the semaphore for a list of elements in the card data.
This release is not necessarily needed.
This commit removes the release to call the function within the critical
section so that later commits are simple.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Pull sound fixes from Takashi Iwai:
"Small last-minute fixes for 4.13-rc1: a couple of PCM fixes for m68k,
a cleanup work for legacy ISA msnd driver, and a few HD-audio new IDs
and quirks"
* tag 'sound-fix-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: hda - Add hdmi id for a Geminilake variant
ALSA: hda/realtek - New codec device ID for ALC1220
ALSA: pcm: Simplify check for dma_mmap_coherent() availability
ALSA: pcm: Protect call to dma_mmap_coherent() by check for HAS_DMA
ALSA: msnd: Optimize / harden DSP and MIDI loops
ALSA: hda/realtek - change the location for one of two front microphones
ALSA: opl4: Move inline before return type
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We check the availability of dma_mmap_coherent() in hw_support_mmap()
but with an ugly ifdef of lots of arch-checks. Now we have a nice
CONFIG_ARCH_NO_COHERENT_DMA_MMAP kconfig, and this can be used
together with CONFIG_HAS_DMA check for a cleaner and more
comprehensive check.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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If NO_DMA=y:
sound/core/pcm_native.o: In function `snd_pcm_lib_default_mmap':
pcm_native.c:(.text+0x144c): undefined reference to `bad_dma_ops'
pcm_native.c:(.text+0x1474): undefined reference to `dma_common_mmap'
Add a check for HAS_DMA to fix this.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Pull sound updates from Takashi Iwai:
"This development cycle resulted in a fair amount of changes in both
core and driver sides. The most significant change in ALSA core is
about PCM. Also the support of of-graph card and the new DAPM widget
for DSP are noteworthy changes in ASoC core. And there're lots of
small changes splat over the tree, as you can see in diffstat.
Below are a few highlights:
ALSA core:
- Removal of set_fs() hackery from PCM core stuff, and the code
reorganization / optimization thereafter
- Improved support of PCM ack ops, and a new ABI for improved
control/status mmap handling
- Lots of constifications in various codes
ASoC core:
- The support of of-graph card, which may work as a better generic
device for a replacement of simple-card
- New widget types intended mainly for use with DSPs
ASoC drivers:
- New drivers for Allwinner V3s SoCs
- Ensonic ES8316 codec support
- More Intel SKL and KBL works
- More device support for Intel SST Atom (mostly for cheap tablets
and 2-in-1 devices)
- Support for Rockchip PDM controllers
- Support for STM32 I2S and S/PDIF controllers
- Support for ZTE AUD96P22 codecs
HD-audio:
- Support of new Realtek codecs (ALC215/ALC285/ALC289), more quirks
for HP and Dell machines
- A few more fixes for i915 component binding"
* tag 'sound-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (418 commits)
ALSA: hda - Fix unbalance of i915 module refcount
ASoC: Intel: Skylake: Remove driver debugfs exit
ASoC: Intel: Skylake: explicitly add the headers sst-dsp.h
ALSA: hda/realtek - Remove GPIO_MASK
ALSA: hda/realtek - Fix typo of pincfg for Dell quirk
ALSA: pcm: add a documentation for tracepoints
ALSA: atmel: ac97c: fix error return code in atmel_ac97c_probe()
ALSA: x86: fix error return code in hdmi_lpe_audio_probe()
ASoC: Intel: Skylake: Add support to read firmware registers
ASoC: Intel: Skylake: Add sram address to sst_addr structure
ASoC: Intel: Skylake: Debugfs facility to dump module config
ASoC: Intel: Skylake: Add debugfs support
ASoC: fix semicolon.cocci warnings
ASoC: rt5645: Add quirk override by module option
ASoC: rsnd: make arrays path and cmd_case static const
ASoC: audio-graph-card: add widgets and routing for external amplifier support
ASoC: audio-graph-card: update bindings for amplifier support
ASoC: rt5665: calibration should be done before jack detection
ASoC: rsnd: constify dev_pm_ops structures.
ASoC: nau8825: change crosstalk-bypass property to bool type
...
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attribute_groups are not supposed to change at runtime. All functions
working with attribute_groups provided by <linux/device.h> work with const
attribute_group. So mark the non-const structs as const.
File size before:
text data bss dec hex filename
9781 240 8 10029 272d sound/core/pcm.o
File size After adding 'const':
text data bss dec hex filename
9813 176 8 9997 270d sound/core/pcm.o
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Now that user-space (typically alsa-lib) can specify which protocol
version it supports, we can optimize the kernel code depending on the
reported protocol version.
In this patch, we change the previous hack for enforcing the appl_ptr
sync by disabling status/control mmap. Instead of forcibly disabling
both mmaps, we disable only the control mmap when user-space declares
the supported protocol version new enough. For older user-space,
still both PCM status and control mmaps are disabled when requested by
the driver due to the compatibility reason.
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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We have an ioctl to inform the PCM protocol version the running kernel
supports, but there is no way to know which protocol version the
user-space can understand. This lack of information caused headaches
in the past when we tried to extend the ABI. For example, because we
couldn't guarantee the validity of the reserved bytes, we had to
introduce a new ioctl SNDRV_PCM_IOCTL_STATUS_EXT for assigning a few
new fields in the formerly reserved bits. If we could know that it's
a new alsa-lib, we could assume the availability of the new fields,
thus we could have reused the existing SNDRV_PCM_IOCTL_STATUS.
In order to improve the ABI extensibility, this patch adds a new ioctl
for user-space to inform its supporting protocol version to the
kernel. By reporting the supported protocol from user-space, the
kernel can judge which feature should be provided and which not.
With the addition of the new ioctl, the PCM protocol version is bumped
to 2.0.14, too. User-space checks the kernel protocol version via
SNDRV_PCM_INFO_PVERSION, then it sets the supported version back via
SNDRV_PCM_INFO_USER_PVERSION.
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Currently x86 platforms use the PCM status/control mmaps for
transferring the PCM status and appl_ptr between kernel and
user-spaces. The mmap is a most efficient way of communication, but
it has a drawback per its nature, namely, it can't notify the change
explicitly to kernel.
The lack of appl_ptr update notification is a problem on a few
existing drivers, but it's mostly a small issue and negligible.
However, a new type of driver that uses DSP for a deep buffer
management requires the exact position of appl_ptr for calculating the
buffer prefetch size, and the asynchronous appl_ptr update between
kernel and user-spaces becomes a significant problem for it.
How can we enforce user-space to report the appl_ptr update? The way
is relatively simple. Just by disabling the PCM control mmap, the
user-space is supposed to fall back to the mode using SYNC_PTR ioctl,
and the kernel gets control over that. This fallback mode is used in
all non-x86 platforms as default, and also in the 32bit compatible
model on all platforms including x86. It's been implemented already
over a decade, so we can say it's fairly safe and stably working.
With the help of the knowledge above, this patch introduces a new PCM
info flag SNDRV_PCM_INFO_SYNC_APPLPTR for achieving the appl_ptr sync
from user-space. When a driver sets this flag at open, the PCM status
/ control mmap is disabled, which effectively switches to SYNC_PTR
mode in user-space side.
In this version, both PCM status and control mmaps are disabled
although only the latter, control mmap, is the target. It's because
the current alsa-lib implementation supposes that both status and
control mmaps are always coupled, thus it handles a fatal error when
only one of them fails.
Of course, the disablement of the status/control mmaps may bring a
slight performance overhead. Thus, as of now, this should be used
only for the dedicated devices that deserves.
Note that the disablement of mmap is a sort of workaround. In the
later patch, we'll introduce the way to identify the protocol version
alsa-lib supports, and keep mmap working while the sync_ptr is
performed together.
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Rename:
wait_queue_t => wait_queue_entry_t
'wait_queue_t' was always a slight misnomer: its name implies that it's a "queue",
but in reality it's a queue *entry*. The 'real' queue is the wait queue head,
which had to carry the name.
Start sorting this out by renaming it to 'wait_queue_entry_t'.
This also allows the real structure name 'struct __wait_queue' to
lose its double underscore and become 'struct wait_queue_entry',
which is the more canonical nomenclature for such data types.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The ALSA PCM core refers to the appl_ptr value stored on the mmapped
page that is shared between kernel and user-space. Although the
reference is performed in the PCM stream lock, it doesn't guarantee
the atomic access when the value gets updated concurrently from the
user-space on another CPU.
In most of codes, this is no big problem, but still there are a few
places that may result in slight inconsistencies because they access
runtime->control->appl_ptr multiple times; that is, the second read
might be a different value from the first value. It can be even
backward or jumping, as we have no control for it. Hence, the
calculation may give an unexpected value. Luckily, there is no
security vulnerability by that, as far as I've checked. But still we
should address it.
This patch tries to reduce such possible cases. The fix is simple --
we just read once, store it to a local variable and use it for the
rest calculations. The READ_ONCE() macro is used for it in order to
avoid the ill-effect by possible compiler optimizations.
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Just a tidy up to follow the standard EXPORT_SYMBOL*() declarations
in order to improve grep-ability.
- Move EXPORT_SYMBOL*() to the position right after its definition
- Remove superfluous blank line before EXPORT_SYMBOL*() lines
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Just a tidy up to follow the standard EXPORT_SYMBOL*() declarations
in order to improve grep-ability.
- Move EXPORT_SYMBOL*() to the position right after its definition
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Just a tidy up to follow the standard EXPORT_SYMBOL*() declarations
in order to improve grep-ability.
- Move EXPORT_SYMBOL*() to the position right after its definition
- Remove superfluous blank line before EXPORT_SYMBOL*() lines
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Just a tidy up to follow the standard EXPORT_SYMBOL*() declarations
in order to improve grep-ability.
- Remove superfluous blank line before EXPORT_SYMBOL*() lines
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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The standard PCM chmap helper callbacks treat the NULL info->chmap as
a fatal error and spews the kernel warning with stack trace when
CONFIG_SND_DEBUG is on. This was OK, originally it was supposed to be
always static and non-NULL. But, as the recent addition of Intel LPE
audio driver shows, the chmap content may vary dynamically, and it can
be even NULL when disconnected. The user still sees the kernel
warning unnecessarily.
For clearing such a confusion, this patch simply removes the
snd_BUG_ON() in each place, just returns an error without warning.
Cc: <stable@vger.kernel.org> # v4.11+
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Drivers can implement 'struct snd_pcm_ops.ioctl' to handle some requests
from ALSA PCM core. These requests are internal purpose in kernel land.
Usually common set of operations are used for it.
SNDRV_PCM_IOCTL1_INFO is one of the requests. According to code comment,
it has been obsoleted in the old days.
We can see old releases in ftp.alsa-project.org. The command was firstly
introduced in v0.5.0 release as SND_PCM_IOCTL1_INFO, to allow drivers to
fill data of 'struct snd_pcm_channel_info' type. In v0.9.0 release,
this was obsoleted by the other commands for ioctl(2) such as
SNDRV_PCM_IOCTL_CHANNEL_INFO.
This commit removes the long-abandoned command, bye.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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We call ack callback whenever appl_ptr gets updated via
pcm_lib_apply_appl_ptr(). There are various code paths to call this
function. A part of them are for read/write/forward/rewind, where the
appl_ptr is always changed and thus the call of ack is mandatory.
OTOH, another part of code paths are from the explicit user call,
e.g. via SYNC_PTR ioctl. There, we may receive the same appl_ptr
value, and in such a case, calling ack is obviously superfluous.
This patch adds the check of the given appl_ptr value, and returns
immediately if it's no real update.
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Just a code cleanup.
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Calling PREPARE ioctl to the stream in either PAUSED or SUSPENDED
state may confuse some drivers that don't handle the state properly.
Instead of fixing each driver, PCM core should take care of the proper
state change before actually trying to (re-)prepare the stream.
Namely, when the stream is in PAUSED state, it triggers PAUSE_RELEASE,
and when in SUSPENDED state, it triggers STOP, before calling prepare
callbacks.
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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So far, the PCM core refuses DROP ioctl when the stream in the
suspended state. This was basically to avoid the invalid state change
*during* the suspend. But since we protect the power change globally
in the common PCM ioctl caller side, it's guaranteed that
snd_pcm_drop() is called at the right power state. So we can assume
that the drop of stream is safe immediately after SUSPENDED state.
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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All PCM common ioctls should run only in the powered up state, but
currently only a few ioctls do the proper snd_power_lock() and
snd_power_wait() invocations. Instead of adding to each place, do it
commonly in the caller side, so that all these ioctls are assured to
be operated at the power up state.
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Use snd_pcm_action_lock_irq() helper instead of open coding.
No functional change.
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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As long as I know, in userspace, '%c' format on printing format for
tracepoint is replaced with '>c<' by existent tracing program; i.g.
'perf-trace' and 'trace-cmd'. This is inconvenient.
This commit replaces the format with '%s'. The length of letters in the
format string is not changed, thus this commit doesn't increase object
size.
In theory, I should work for improvements of these tracing programs, but
here I'd like to save my time to work for the other projects.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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In design of ALSA PCM core, status and control data for runtime of ALSA
PCM substream are shared between kernel/user spaces by page frame
mapping with read-only attribute. Both of hardware-side and
application-side position on PCM buffer are maintained as a part of
the status data. In a view of ALSA PCM application, these two positions
can be updated by executing ioctl(2) with some commands.
There's an event of tracepoint for hardware-side position; 'hwptr'.
On the other hand, no events for application-side position. This commit
adds a new event for this purpose; 'applptr'. When the application-side
position is changed in kernel space, this event is probed with useful
information for developers.
I note that the event is not probed for all of ALSA PCM applications, When
applications are written by read/write programming scenario, the event is
surely probed. The applications execute ioctl(2) with
SNDRV_PCM_IOCTL_[READ|WRITE][N/I]_FRAMES to read/write any PCM frame, then
ALSA PCM core updates the application-side position in kernel land.
However, when applications are written by mmap programming scenario, if
maintaining the application side position in kernel space accurately,
applications should voluntarily execute ioctl(2) with
SNDRV_PCM_IOCTL_SYNC_PTR to commit the number of handled PCM frames. If
not voluntarily, the application-side position is not changed, thus the
added event is not probed.
There's a loophole, using architectures to which ALSA PCM core judges
non cache coherent. In this case, the status and control data is not mapped
into processe's VMA for any applications. Userland library, alsa-lib, is
programmed for this case. It executes ioctl(2) with
SNDRV_PCM_IOCTL_SYNC_PTR command every time to requiring the status and
control data.
ARM is such an architecture. Below is an example with serial sound interface
(ssi) on i.mx6 quad core SoC. I use v4.1 kernel released by fsl-community
with patches from VIA Tech. Inc. for VAB820, and my backport patches for
relevant features for this patchset. I use Ubuntu 17.04 from
ports.ubuntu.com as user land for armhf architecture.
$ aplay -v -M -D hw:imx6vab820sgtl5,0 /dev/urandom -f S16_LE -r 48000 --period-size=128 --buffer-size=256
Playing raw data '/dev/urandom' : Signed 16 bit Little Endian, Rate 48000 Hz, Mono
Hardware PCM card 0 'imx6-vab820-sgtl5000' device 0 subdevice 0
Its setup is:
stream : PLAYBACK
access : MMAP_INTERLEAVED
format : S16_LE
subformat : STD
channels : 1
rate : 48000
exact rate : 48000 (48000/1)
msbits : 16
buffer_size : 256
period_size : 128
period_time : 2666
tstamp_mode : NONE
tstamp_type : MONOTONIC
period_step : 1
avail_min : 128
period_event : 0
start_threshold : 256
stop_threshold : 256
silence_threshold: 0
silence_size : 0
boundary : 1073741824
appl_ptr : 0
hw_ptr : 0
mmap_area[0] = 0x76f98000,0,16 (16)
$ trace-cmd record -e snd_pcm:hwptr -e snd_pcm:applptr
$ trace-cmd report
...
60.208495: applptr: pcmC0D0p/sub0: prev=1792, curr=1792, avail=0, period=128, buf=256
60.208633: applptr: pcmC0D0p/sub0: prev=1792, curr=1792, avail=0, period=128, buf=256
60.210022: hwptr: pcmC0D0p/sub0: IRQ: pos=128, old=1536, base=1536, period=128, buf=256
60.210202: applptr: pcmC0D0p/sub0: prev=1792, curr=1792, avail=128, period=128, buf=256
60.210344: hwptr: pcmC0D0p/sub0: POS: pos=128, old=1664, base=1536, period=128, buf=256
60.210348: applptr: pcmC0D0p/sub0: prev=1792, curr=1792, avail=128, period=128, buf=256
60.210486: applptr: pcmC0D0p/sub0: prev=1792, curr=1792, avail=128, period=128, buf=256
60.210626: applptr: pcmC0D0p/sub0: prev=1792, curr=1920, avail=0, period=128, buf=256
60.211002: applptr: pcmC0D0p/sub0: prev=1920, curr=1920, avail=0, period=128, buf=256
60.211142: hwptr: pcmC0D0p/sub0: POS: pos=128, old=1664, base=1536, period=128, buf=256
60.211146: applptr: pcmC0D0p/sub0: prev=1920, curr=1920, avail=0, period=128, buf=256
60.211287: applptr: pcmC0D0p/sub0: prev=1920, curr=1920, avail=0, period=128, buf=256
60.212690: hwptr: pcmC0D0p/sub0: IRQ: pos=0, old=1664, base=1536, period=128, buf=256
60.212866: applptr: pcmC0D0p/sub0: prev=1920, curr=1920, avail=128, period=128, buf=256
60.212999: hwptr: pcmC0D0p/sub0: POS: pos=0, old=1792, base=1792, period=128, buf=256
60.213003: applptr: pcmC0D0p/sub0: prev=1920, curr=1920, avail=128, period=128, buf=256
60.213135: applptr: pcmC0D0p/sub0: prev=1920, curr=1920, avail=128, period=128, buf=256
60.213276: applptr: pcmC0D0p/sub0: prev=1920, curr=2048, avail=0, period=128, buf=256
60.213654: applptr: pcmC0D0p/sub0: prev=2048, curr=2048, avail=0, period=128, buf=256
60.213796: hwptr: pcmC0D0p/sub0: POS: pos=0, old=1792, base=1792, period=128, buf=256
60.213800: applptr: pcmC0D0p/sub0: prev=2048, curr=2048, avail=0, period=128, buf=256
60.213937: applptr: pcmC0D0p/sub0: prev=2048, curr=2048, avail=0, period=128, buf=256
60.215356: hwptr: pcmC0D0p/sub0: IRQ: pos=128, old=1792, base=1792, period=128, buf=256
60.215542: applptr: pcmC0D0p/sub0: prev=2048, curr=2048, avail=128, period=128, buf=256
60.215679: hwptr: pcmC0D0p/sub0: POS: pos=128, old=1920, base=1792, period=128, buf=256
60.215683: applptr: pcmC0D0p/sub0: prev=2048, curr=2048, avail=128, period=128, buf=256
60.215813: applptr: pcmC0D0p/sub0: prev=2048, curr=2048, avail=128, period=128, buf=256
60.215947: applptr: pcmC0D0p/sub0: prev=2048, curr=2176, avail=0, period=128, buf=256
...
We can surely see 'applptr' event is probed even if the application run
for mmap programming scenario ('-M' option and 'hw' plugin). Below is a
result of strace:
02:44:15.886382 ioctl(4, SNDRV_PCM_IOCTL_SYNC_PTR, 0x56a32b30) = 0
02:44:15.887203 poll([{fd=4, events=POLLOUT|POLLERR|POLLNVAL}], 1, -1) = 1 ([{fd=4, revents=POLLOUT}])
02:44:15.887471 ioctl(4, SNDRV_PCM_IOCTL_SYNC_PTR, 0x56a32b30) = 0
02:44:15.887637 ioctl(4, SNDRV_PCM_IOCTL_SYNC_PTR, 0x56a32b30) = 0
02:44:15.887805 ioctl(4, SNDRV_PCM_IOCTL_SYNC_PTR, 0x56a32b30) = 0
02:44:15.887969 ioctl(4, SNDRV_PCM_IOCTL_SYNC_PTR, 0x56a32b30) = 0
02:44:15.888132 read(3, "..."..., 256) = 256
02:44:15.889040 ioctl(4, SNDRV_PCM_IOCTL_SYNC_PTR, 0x56a32b30) = 0
02:44:15.889221 ioctl(4, SNDRV_PCM_IOCTL_SYNC_PTR, 0x56a32b30) = 0
02:44:15.889431 ioctl(4, SNDRV_PCM_IOCTL_SYNC_PTR, 0x56a32b30) = 0
02:44:15.889606 poll([{fd=4, events=POLLOUT|POLLERR|POLLNVAL}], 1, -1) = 1 ([{fd=4, revents=POLLOUT}])
02:44:15.889833 ioctl(4, SNDRV_PCM_IOCTL_SYNC_PTR, 0x56a32b30) = 0
02:44:15.889998 ioctl(4, SNDRV_PCM_IOCTL_SYNC_PTR, 0x56a32b30) = 0
02:44:15.890164 ioctl(4, SNDRV_PCM_IOCTL_SYNC_PTR, 0x56a32b30) = 0
02:44:15.891048 ioctl(4, SNDRV_PCM_IOCTL_SYNC_PTR, 0x56a32b30) = 0
02:44:15.891228 read(3, "..."..., 256) = 256
02:44:15.891497 ioctl(4, SNDRV_PCM_IOCTL_SYNC_PTR, 0x56a32b30) = 0
02:44:15.891661 ioctl(4, SNDRV_PCM_IOCTL_SYNC_PTR, 0x56a32b30) = 0
02:44:15.891829 ioctl(4, SNDRV_PCM_IOCTL_SYNC_PTR, 0x56a32b30) = 0
02:44:15.891991 poll([{fd=4, events=POLLOUT|POLLERR|POLLNVAL}], 1, -1) = 1 ([{fd=4, revents=POLLOUT}])
02:44:15.893007 ioctl(4, SNDRV_PCM_IOCTL_SYNC_PTR, 0x56a32b30) = 0
We can see 7 calls of ioctl(2) with SNDRV_PCM_IOCTL_SYNC_PTR per loop with
call of poll(2). 128 PCM frames are transferred per loop of one poll(2),
because the PCM substream is configured with S16_LE format and 1 channel
(2 byte * 1 * 128 = 256 bytes). This equals to the size of period of PCM
buffer. Comparing to the probed data, one of the 7 calls of ioctl(2) is
actually used to commit the number of copied PCM frames to kernel space.
The other calls are just used to check runtime status of PCM substream;
e.g. XRUN.
The tracepoint event is useful to investigate this case. I note that below
modules are related to the above sample.
* snd-soc-dummy.ko
* snd-soc-imx-sgtl5000.ko
* snd-soc-fsl-ssi.ko
* snd-soc-imx-pcm-dma.ko
* snd-soc-sgtl5000.ko
My additional note is lock acquisition. The event is probed under acquiring
PCM stream lock. This means that calculation in the event is free from
any hardware events.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
|
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In a series of recent work, ALSA PCM core got some arrangements to handle
application-side position on PCM buffer. However, relevant codes still
disperse to two translation units
This commit unifies these codes into a helper function.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
|
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Many drivers bind the sequencer stuff in off-load by another driver
module, so that it's loaded only on demand. In the current code, this
mechanism doesn't work when the driver is built-in while the sequencer
is module. We check with IS_REACHABLE() and enable only when the
sequencer is in the same level of build.
However, this is basically a overshoot. The binder code
(snd-seq-device) is an individual module from the sequencer core
(snd-seq), and we just have to make the former a built-in while
keeping the latter a module for allowing the scenario like the above.
This patch achieves that by rewriting Kconfig slightly. Now, a driver
that provides the manual sequencer device binding should select
CONFIG_SND_SEQ_DEVICE in a way as
select SND_SEQ_DEVICE if SND_SEQUENCER != n
Note that the "!=n" is needed here to avoid the influence of the
sequencer core is module while the driver is built-in.
Also, since rawmidi.o may be linked with snd_seq_device.o when
built-in, we have to shuffle the code to make the linker happy.
(the kernel linker isn't smart enough yet to handle such a case.)
That is, snd_seq_device.c is moved to sound/core from sound/core/seq,
as well as Makefile.
Last but not least, the patch replaces the code using IS_REACHABLE()
with IS_ENABLED(), since now the condition meets always when enabled.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
|
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At present, trace events are probed even if corresponding parameter is
not actually changed. This is inconvenient.
This commit improves the behaviour.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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When refining mask/interval parameters, helper functions can return error
code. This error is not handled immediately. This seems to return
parameters to userspace applications in its meddle of processing.
However, in general, when receiving error from system calls, the
application might not handle argument buffer. It's reasonable to
judge the above design as superfluity.
This commit handles the error immediately.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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This is a slightly intensive rewrite of Kconfig and Makefile about
ALSA sequencer stuff.
The first major change is that the kconfig items for the sequencer are
moved to sound/core/seq/Kconfig. OK, that's easy.
The substantial change is that, instead of hackish top-level module
selection in Makefile, we define a Kconfig item for each sequencer
module. The driver that requires such sequencer components select
exclusively the kconfig items. This is more straightforward and
standard way.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
|
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Currently OSS sequencer emulation is tied with ALSA sequencer core,
both are built in the same level; i.e. when CONFIG_SND_SEQUENCER=y,
the OSS sequencer emulation is also always built-in, even though the
functionality can be built as an individual module.
This patch changes the rule and allows users to build snd-seq-oss
module while others are built-in. Essentially, it's just a few simple
changes in Kconfig and Makefile. Some driver codes like opl3 need to
convert from the simple ifdef to IS_ENABLED(). But that's all.
You might wonder how about the dependency: right, it can be messy, but
it still works. Since we rewrote the sequencer binding with the
standard bus, the driver can be bound at any time on demand. So, the
synthesizer driver module can be loaded individually from the OSS
emulation core before/after it.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
|
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Currently CONFIG_SND_OSSEMUL is selected by each config like
CONFIG_SND_PCM_OSS. But, as see in the raw MIDI code that is built
conditionally with CONFIG_SND_OSSEMUL, we should rather make
CONFIG_SND_OSSEMUL user-selectable as the top kconfig item, and leave
the rest depending on it.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
|
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Use the same print format of snd_pcm_debug_name() for userspace tracing
program.
Suggested-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
|
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Results of ioctl(2) with SNDRV_PCM_IOCTL_HW_REFINE and
SNDRV_PCM_IOCTL_HW_PARAMS are different, because the latter has single
value for several parameters; e.g. channels of PCM substream. Selection
of the single value is done independently of application of constraints.
It's helpful for developers to trace the selection process.
This commit adds tracepoints to snd_pcm_hw_params_choose() for the
purpose.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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As of v4.12, snd_pcm_hw_params_choose() is just called in a process
context of ioctl(2) with SNDRV_PCM_IOCTL_HW_PARAMS. The function locates
in a different file, which has no tracepoints.
This commit moves the function to a file with the tracepoints for later
commit.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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When drivers register no flags about information of PCM hardware, ALSA
PCM core fixups it roughly. Currently, this operation places in a
function snd_pcm_hw_refine(). It can be moved to a function
fixup_unreferenced_params() because it doesn't affects operations
between these two functions.
This idea is better to bundle codes with similar purposes and this commit
achieves it.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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A structure for parameters of PCM runtime has parameters which are
not classified as mask/interval type. They are decided only when
corresponding normal parameters have unique values.
* struct snd_pcm_hw_params.msbits
* struct snd_pcm_hw_params.rate_num
* struct snd_pcm_hw_params.rate_den
* struct snd_pcm_hw_params.fifo_size
Current implementation of hw_params ioctl sometimes doesn't decide these
parameters even if corresponding parameters are fixed, because these
parameters are evaluated before a call of snd_pcm_hw_params_choose().
This commit adds a helper function to process the parameters and call it
in proper positions.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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To fixup some parameters, ALSA PCM core refers the other parameters as
constants. There're some macros for this purpose.
This commit replaces codes with them.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Drivers add rules of parameters to runtime of PCM substream, when
applications open ALSA PCM character device. When applications call
ioctl(2) with SNDRV_PCM_IOCTL_HW_REFINE or SNDRV_PCM_IOCTL_HW_PARAMS, the
rules are applied to the parameters and return the result to user space.
The rule can have dependency between parameters. Additionally, it can have
condition flags about application of rules. Userspace applications can
indicate the flags to suppress change of parameters.
This commit attempts to describe the mechanism.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Takashi Sakamoto
Daniel Mentz
Takashi Iwai
Linus Torvalds
Geert Uytterhoeven
Arvind Yadav
Ingo Molnar