sound: Handle unavailable devices in various OSS IOCTLs

mixer(8)'s -a option is used to print information about all mixer
devices in the system. To do this, it loops from 0 to
mixer_get_nmixers(), and tries to open "/dev/mixer%d". However, this
approach doesn't work when there are disabled/unregistered mixers in the
system, or when an audio device simply doesn't have a mixer.

mixer_get_nmixers() calls SNDCTL_SYSINFO and returns
oss_sysinfo->nummixers, whose value is the number of currently _enabled_
mixers only. Taking the bug report mentioned below (277615) as an
example, suppose a system with 8 mixer devices total, but 3 of them are
either disabled or non-existent, which means they will not show up under
/dev, meaning we have 5 enabled mixer devices, which is also what the
value of oss_sysinfo->nummixers will be. What mixer(8) will do is loop
from 0 to 5 (instead of 8), and start calling mixer_open() on
/dev/mixer0, up to /dev/mixer4, and as is expected, the first call will
fail right away, hence the error shown in the bug report.

To fix this, modify oss_sysinfo->nummixers to hold the value of the
maximum unit in the system, which, although not necessarily "correct",
is more intuitive for applications that will want to use this value to
loop through all mixer devices.

Additionally, notify applications that a device is
unavailable/unregistered instead of skipping it. The current
implementations of SNDCTL_AUDIOINFO, SNDCTL_MIXERINFO and
SNDCTL_CARDINFO break applications that expect to get information about
a device that is skipped. Related discussion can be found here:
https://reviews.freebsd.org/D45135#1029526

It has to be noted, that other applications, apart from mixer(8), suffer
from this.

PR: 277615
Sponsored by: The FreeBSD Foundation
MFC after: 1 day
Reviewed by: dev_submerge.ch
Differential Revision: https://reviews.freebsd.org/D45256

sound: Separate implementations for SNDCTL_AUDIOINFO[_EX] and SNDCTL_ENGINEINFO

FreeBSD's implementation of SNDCTL_AUDIOINFO[_EX] and SNDCTL_ENGINEINFO
does not exactly work as intended. The problem is essentially that both
IOCTLs return the same information, while in fact the information
returned currently by dsp_oss_audioinfo() is what _only_
SNDCTL_ENGINEINFO is meant to return.

This behavior is also noted in the OSS manual [1] (see bold paragraph in
"Audio engines and device files" section), but since e8c0d15a64fa
("sound: Get rid of snd_clone and use DEVFS_CDEVPRIV(9)") we can
actually fix this, because we now expose only a single device for each
soundcard, and create the engines (channels) internally.
SNDCTL_ENGINEINFO will now report info about all channels in a given
device, and SNDCTL_AUDIOINFO[_EX] will only report information about
/dev/dspX.

To make this work, we also have to modify the SNDCTL_SYSINFO IOCTL to
report the number of audio devices and audio engines correctly.

While here, modernize the minimum and maximum channel counting in both
SNDCTL_AUDIOINFO[_EX] and SNDCTL_ENGINEINFO. Currently these IOCTLs will
report only up to 2 channels, which is no longer the case.

[1] http://manuals.opensound.com/developer/SNDCTL_AUDIOINFO.html

PR: 246231, 252761
Sponsored by: The FreeBSD Foundation
MFC after: 1 day
Reviewed by: dev_submerge.ch
Differential Revision: https://reviews.freebsd.org/D45164

sound: Remove ncards variable from sound_oss_card_info()

The loop counter is also the card's index, so ncards is redundant.

Sponsored by: The FreeBSD Foundation
MFC after: 3 days
Reviewed by: dev_submerge.ch
Differential Revision: https://reviews.freebsd.org/D45144

sound: Fix oss_sysinfo->numcards

According to the OSS manual, oss_sysinfo->numcards holds the number of
detected audio devices in the system, while the current ncards variable,
whose value is assigned to oss_sysinfo->numcards, holds the number of
currently registered devices only.

Sponsored by: The FreeBSD Foundation
MFC after: 3 days
Reviewed by: dev_submerge.ch, emaste
Differential Revision: https://reviews.freebsd.org/D45136

sound: Remove unused "num" argument from chn_init() and related callers

It is always -1 (i.e unused).

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Reviewed by: dev_submerge.ch
Differential Revision: https://reviews.freebsd.org/D45095

sound: Move vchan-related code to pcm/vchan.*

pcm/sound.* contains code that should be part of pcm/vchan.*.

Changes:
- pcm_setvchans() -> vchan_setnew()
- pcm_setmaxautovchans() -> vchan_setmaxauto()
- hw.snd.maxautovchans moved to pcm/vchan.c
- snd_maxautovchans declaration moved to pcm/vchan.h and definition to
pcm/vchan.c

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Reviewed by: dev_submerge.ch, markj
Differential Revision: https://reviews.freebsd.org/D45015

sound: Use nitems() where possible

No functional change intended.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Reviewed by: markj, emaste
Differential Revision: https://reviews.freebsd.org/D45014

sound: Remove hw.snd.version and SND_DRV_VERSION

hw.snd.version and SND_DRV_VERSION define the sound driver version and
are meant to be used in bug reports, but because these values are
constant, there is not much useful information we can extract from them.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Reviewed by: dev_submerge.ch, emaste
Differential Revision: https://reviews.freebsd.org/D44996

sound: Convert pcm_chn_add() to void

It always returns 0.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Reviewed by: markj, emaste
Differential Revision: https://reviews.freebsd.org/D44998

sound: Add __assert_unreachable() to default cases in pcm_chn_add() and pcm_chn_remove()

We should normally never enter these cases.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Reviewed by: markj, emaste
Differential Revision: https://reviews.freebsd.org/D44994

sound: Merge pcm_chn_create() and chn_init()

Follow-up of b3ea087c05d8c75978a302cbb3fa92ce1afa3e49 ("sound: Merge
pcm_chn_destroy() and chn_kill()")

While here, add device_printf()'s to all failure points. Also fix an
existing bug where we'd unlock an already unlocked channel, in case we
went to "out" (now "out2") before locking the channel.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Reviewed by: dev_submerge.ch
Differential Revision: https://reviews.freebsd.org/D44993

sound: Add missing space in dev.pcm.X.mode description

Sponsored by: The FreeBSD Foundation
MFC after: 1 day
Reviewed by: markj, emaste
Differential Revision: https://reviews.freebsd.org/D44990

sound: Move pcm_chnref() and pcm_chnrelease() to pcm/channel.c

Improve code layering. These are channel functions, and so they do not
belong in pcm/sound.c.

While here, assert in chn_ref() that new refcount won't be negative.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D44985

sound: Merge pcm_chn_destroy() and chn_kill()

pcm_chn_destroy() acts like a wrapper around chn_kill(), and
additionally calls a few more functions that should in fact be part of
chn_kill()'s logic. Merge pcm_chn_destroy()'s functionality in
chn_kill() to improve readability, as well as code layering.

While here, convert chn_kill() to void as it currently always returns 0.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D44984

sound: Retire unit.*

The unit.* code is largely obsolete and imposes limits that are no
longer needed nowadays.

- Capping the maximum allowed soundcards in a given machine. By default,
the limit is 512 (snd_max_u() in unit.c), and the maximum possible is
2048 (SND_UNIT_UMAX in unit.h). It can also be tuned through the
hw.snd.maxunit loader(8) tunable. Even though these limits are large
enough that they should never cause problems, there is no need for
this limit to exist in the first place.
- Capping the available device/channel types. By default, this is 32
(snd_max_d() in unit.c). However, these types are pre-defined in
pcm/sound.h (see SND_DEV_*), so the cap is unnecessary when we know
that their number is constant.
- Capping the number of channels per-device. By default, the limit 1024
(snd_max_c() in unit.c). This is probably the most problematic of the
limits mentioned, because this limit can never be reached, as the
maximum is hard-capped at either hw.snd.maxautovchans (16 by default),
or SND_MAXHWCHAN and SND_MAXVCHANS.

These limtits are encoded in masks (see SND_U_MASK, SND_D_MASK,
SND_C_MASK in unit.h) and are used to construct a bitfield of the form
[dsp_unit, type, channel_unit] in snd_mkunit() which is assigned to
pcm_channel->unit.

This patch gets rid of everything unit.*-related and makes a slightly
different use of the "unit" field to only contain the channel unit
number. The channel type is stored in a new pcm_channel->type field, and
the DSP unit number need not be stored at all, since we can fetch it
from device_get_unit(pcm_channel->dev). This change has the effect that
we no longer need to impose caps on the number of soundcards,
device/channel types and per-device channels. As a result the code is
noticeably simplified and more readable.

Apart from the fact that the hw.snd.maxunit loader(8) tunable is also
retired as a side-effect of this patch, sound(4)'s behavior remains the
same.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Reviewed by: dev_submerge.ch
Differential Revision: https://reviews.freebsd.org/D44912

sound: Fix panic caused by sleeping-channel destruction during asynchronous detach

Currently we are force-destroying all channels unconditionally in
pcm_killchan(). However, since asynchronous audio device detach is
possible as of 44e128fe9d92, if we do not check whether the channel is
sleeping or not and forcefully kill it, we will get a panic from
cv_timedwait_sig() (called from chn_sleep()), because it will try to use
a freed lock/cv.

Modify pcm_killchan() (renamed to pcm_killchans() since that's a more
appropriate name now) to loop through the channel list and destroy only
the channels that are awake, otherwise wake up the sleeping thread and
try again. This loop is repeated until all channels are awakened and
destroyed.

To reduce code duplication, implement chn_shutdown() which wakes up the
channel and sets CHN_F_DEAD, and use it in pcm_unregister() and
pcm_killchans().

Reported by: KASAN
Fixes: 44e128fe9d92 ("sound: Implement asynchronous device detach")
Sponsored by: The FreeBSD Foundation
MFC after: 1 day
Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D44923

sound: Fix NULL dereference in dsp_clone() and mixer_clone()

If we only have a single soundcard attached and we detach it right
before entering [dsp|mixer]_clone(), there is a chance pcm_unregister()
will have returned already, meaning it will have set snd_unit to -1, and
thus devclass_get_softc() will return NULL here.

While here, 1) move the calls to dsp_destroy_dev() and mixer_uninit()
below the point where we unset SD_F_REGISTERED, and 2) follow what
mixer_clone() does and make sure we don't use a NULL d->dsp_dev in
dsp_clone().

Reported by: KASAN
Sponsored by: The FreeBSD Foundation
MFC after: 1 day
Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D44924

sound: Get rid of snddev_info->devcount

snddev_info->devcount keeps track of the total number of channels for a
given device. However, it is redundant to have it, since it is only used
in sound_oss_sysinfo() to populate the "numaudios" field, and we also
keep track of the channel counts in the playcount, pvchancount, reccount
and rvchancount fields anyway. We can simply sum those fields together
instead of updating a separate variable upon every channel
addition/deletion.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D44852

sound: Be more verbose with virtual channel descriptions

Non-virtual channel description denote "play" or "record", so do the
same for virtual ones as well.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Reviewed by: markj, emaste
Differential Revision: https://reviews.freebsd.org/D44839

sound: Update some LICENSE headers

The following commits introduced substantial changes to pcm/dsp.c,
pcm/sndstat.c and pcm/sound.c.

9da3b645dbaaad724d524727d003fed7be05ff7c ("sound: Move
sndstat_prepare_pcm() to pcm/sndstat.c and remove
sndstat_entry->handler")
e8c0d15a64fadb4a330f2da7244becaac161bb70 ("sound: Get rid of snd_clone
and use DEVFS_CDEVPRIV(9)")

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D44757

sound: Implement asynchronous device detach

Hot-unplugging a sound device, such as a USB sound card, whilst being
consumed by an application, results in an infinite loop until either the
application closes the device's file descriptor, or the channel
automatically times out after hw.snd.timeout seconds. In the case of a
detach however, the timeout approach is still not ideal, since we want
all resources to be released immediatelly, without waiting for N seconds
until we can use the bus again.

The timeout mechanism works by calling chn_sleep() in chn_read() and
chn_write() (see pcm/channel.c) in order to send the thread to sleep,
using cv_timedwait_sig(). Since chn_sleep() sets the CHN_F_SLEEPING flag
while waiting for cv_timedwait_sig() to return, we can test this flag in
pcm_unregister() (called during detach) and wakeup the sleeping
thread(s) to immediately kill the channel(s) being consumed.

Sponsored by: The FreeBSD Foundation
MFC after: 2 months
PR: 194727
Reviewed by: dev_submerge.ch, bapt, markj
Differential Revision: https://reviews.freebsd.org/D43545

sound: Get rid of snd_clone and use DEVFS_CDEVPRIV(9)

Currently the snd_clone framework creates device nodes on-demand for
every channel, through the dsp_clone() callback, and is responsible for
routing audio to the appropriate channel(s). This patch gets rid of the
whole snd_clone framework (including any related sysctls) and instead
uses DEVFS_CDEVPRIV(9) to handle device opening, channel allocation and
audio routing. This results in a significant reduction in code size as
well as complexity.

Behavior that is preserved:

- hw.snd.basename_clone.
- Exclusive access of an audio device (i.e VCHANs disabled).
- Multiple processes can read from/write to the device.
- A device can only be opened as many times as the maximum allowed
channel number (see SND_MAXHWCHAN in pcm/sound.h).
- OSSv4 compatibility aliases are preserved.

Behavior changes:

Only one /dev/dspX device node is created (on attach) for each audio
device, as opposed to the current /dev/dspX.Y devices created by
snd_clone. According to the sound(4) man page, devices are not meant to
be opened through /dev/dspX.Y anyway, so it is best if we do not create
device nodes for them in the first place. As a result of this, modify
dsp_oss_audioinfo() to print /dev/dspX in the "ai->devnode", instead of
/dev/dspX.Y.

Sponsored by: The FreeBSD Foundation
MFC after: 2 months
Reviewed by: dev_submerge.ch, bapt, markj
Differential Revision: https://reviews.freebsd.org/D44411

Revert "sound: Get rid of snd_clone and use DEVFS_CDEVPRIV(9)"

This reverts commit dc831e93bad63f9faea09f1806a7733a40bff316.

After several reports in the mailing lists, this commit breaks
pulseaudio. Revert until the issue is resolved.

Revert "sound: Implement asynchronous device detach"

This reverts commit 9eff58c6d52b66eb8abe7f724dabcd804a566df4.

We are reverting dc831e93bad6 ("sound: Get rid of snd_clone and use
DEVFS_CDEVPRIV(9)"), so revert this commit as well since it depends
dc831e93bad6.

sound: Move sndstat_prepare_pcm() to pcm/sndstat.c and remove sndstat_entry->handler

Since all sndstat_entry->handler fields point to sndstat_prepare_pcm(),
we can just call the function directly, without assigning it to a
function pointer and calling it indirectly.

While here, move sndstat_prepare_pcm() to pcm/sndstat.c, as it is more
suitable there.

No functional change intended.

Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Reviewed by: dev_submerge.ch, markj
Differential Revision: https://reviews.freebsd.org/D44571

sound: Implement asynchronous device detach

Hot-unplugging a sound device, such as a USB sound card, whilst being
consumed by an application, results in an infinite loop until either the
application closes the device's file descriptor, or the channel
automatically times out after hw.snd.timeout seconds. In the case of a
detach however, the timeout approach is still not ideal, since we want
all resources to be released immediatelly, without waiting for N seconds
until we can use the bus again.

The timeout mechanism works by calling chn_sleep() in chn_read() and
chn_write() (see pcm/channel.c) in order to send the thread to sleep,
using cv_timedwait_sig(). Since chn_sleep() sets the CHN_F_SLEEPING flag
while waiting for cv_timedwait_sig() to return, we can test this flag in
pcm_unregister() (called during detach) and wakeup the sleeping
thread(s) to immediately kill the channel(s) being consumed.

Sponsored by: The FreeBSD Foundation
MFC after: 2 months
PR: 194727, 278055, 202275, 220949, 272286
Reviewed by: dev_submerge.ch, markj
Differential Revision: https://reviews.freebsd.org/D43545

sound: Get rid of snd_clone and use DEVFS_CDEVPRIV(9)

Currently the snd_clone framework creates device nodes on-demand for
every channel, through the dsp_clone() callback, and is responsible for
routing audio to the appropriate channel(s). This patch gets rid of the
whole snd_clone framework (including any related sysctls) and instead
uses DEVFS_CDEVPRIV(9) to handle device opening, channel allocation and
audio routing. This results in a significant reduction in code size as
well as complexity.

Behavior that is preserved:

- hw.snd.basename_clone.
- Exclusive access of an audio device (i.e VCHANs disabled).
- Multiple processes can read from/write to the device.
- A device can only be opened as many times as the maximum allowed
channel number (see SND_MAXHWCHAN in pcm/sound.h).
- OSSv4 compatibility aliases are preserved.

Behavior changes:

Only one /dev/dspX device node is created (on attach) for each audio
device, as opposed to the current /dev/dspX.Y devices created by
snd_clone. According to the sound(4) man page, devices are not meant to
be opened through /dev/dspX.Y anyway, so it is best if we do not create
device nodes for them in the first place. As a result of this, modify
dsp_oss_audioinfo() to print /dev/dspX in the "ai->devnode", instead of
/dev/dspX.Y.

Sponsored by: The FreeBSD Foundation
MFC after: 2 months
Reviewed by: dev_submerge.ch, markj
Differential Revision: https://reviews.freebsd.org/D44411

sound: Get rid of pcm/sndstat.h and turn macros into regular code

There is no reason to have macros for this. Putting the code in
sndstat_prepare_pcm() directly makes it easier to work with it.

No functional change intended.

Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D44545

sound: remove snddev_info->inprog and pcm_inprog()

No longer used.

Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D43737

sys: Remove SND_DECLARE_FILE

Reviewed by: kbowling, imp, emaste
Differential Revision: https://reviews.freebsd.org/D41499

sys: Remove $FreeBSD$: sound driver version

Remove /SND_DECLARE_FILE\("\$FreeBSD\$"\);/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

pcm: Initialize pcm_devclass in sound_modevent.

Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D34998

pcm: Remove dead code from sound_modevent.

Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D34997

sound: Remove CTLFLAG_NEEDGIANT from some sysctls.

While there, remove some dead code.

MFC after: 2 weeks

pcm: plug set-but-not-used vars

Sponsored by: Rubicon Communications, LLC ("Netgate")

sound(4): Implement playback and recording mode sysctl(8).

The dev.pcm.<N>.mode sysctl(8) gives information if a sound device
supports hardware mixing, playback or recording.

Submitted by: Christos Margiolis <christos@freebsd.org>
Differential Revision: https://reviews.freebsd.org/D31320
MFC after: 1 week
Sponsored by: NVIDIA Networking

sound(4): Fix typos.

Submitted by: Christos Margiolis <christos@freebsd.org>
Differential Revision: https://reviews.freebsd.org/D31320
MFC after: 1 week
Sponsored by: NVIDIA Networking

sound: clean up empty lines in .c and .h files

Implement a detaching flag for the sound(4) subsystem to take
appropriate actions when we are trying to detach an audio device,
but cannot because someone is using it.

This avoids applications having to wait for the DSP read data
timeout before they receive any error indication.
Tested with virtual_oss(8).

Remove some unused definitions while at it.

PR: 194727
MFC after: 1 week
Sponsored by: Mellanox Technologies

Mark more nodes as CTLFLAG_MPSAFE or CTLFLAG_NEEDGIANT (17 of many)

r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are
still not MPSAFE (or already are but aren’t properly marked).
Use it in preparation for a general review of all nodes.

This is non-functional change that adds annotations to SYSCTL_NODE and
SYSCTL_PROC nodes using one of the soon-to-be-required flags.

Mark all obvious cases as MPSAFE. All entries that haven't been marked
as MPSAFE before are by default marked as NEEDGIANT

Approved by: kib (mentor, blanket)
Commented by: kib, gallatin, melifaro
Differential Revision: https://reviews.freebsd.org/D23718

sys/dev: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

To support userspace audio daemons like Virtual OSS, /dev/sndstat is
made writeable by the root user. Userspace audio daemons can add or
update an entry in /dev/sndstat by doing a single system write call to
any /dev/sndstat file descriptor handle. When the audio daemon closes the
file handle or is killed the entry disappears.

While at it, cleanup the sound status code a bit:
- keep the device list sorted to avoid sorting the list every time a
/dev/sndstat read request is made.
- factor out locking into a pair of locking macros.
- use the sound status lock to protect all per file handle states,
when generating the output for /dev/sndstat and when removing or
adding sound status devices. This way sndstat_acquire() and
sndstat_release() become superfluous and can be removed.

Reviewed by: mav @
Differential Revision: https://reviews.freebsd.org/D5191

Make all PCM core sysctls tunable and remove redundant TUNABLE()
statements. This allows for setting all PCM core parameters in the
kernel environment through loader.conf(5) or kenv(1) which is useful
for pluggable PCM devices like USB audio devices which might be
plugged after that sysctl.conf(5) is executed.

Remove check for obsolete FreeBSD versions

PR: 194517
Submitted by: François Tigeot <ftigeot@wolfpond.org>

Pull in r267961 and r267973 again. Fix for issues reported will follow.

Revert r267961, r267973:

These changes prevent sysctl(8) from returning proper output,
such as:

1) no output from sysctl(8)
2) erroneously returning ENOMEM with tools like truss(1)
or uname(1)
truss: can not get etype: Cannot allocate memory

Extend the meaning of the CTLFLAG_TUN flag to automatically check if
there is an environment variable which shall initialize the SYSCTL
during early boot. This works for all SYSCTL types both statically and
dynamically created ones, except for the SYSCTL NODE type and SYSCTLs
which belong to VNETs. A new flag, CTLFLAG_NOFETCH, has been added to
be used in the case a tunable sysctl has a custom initialisation
function allowing the sysctl to still be marked as a tunable. The
kernel SYSCTL API is mostly the same, with a few exceptions for some
special operations like iterating childrens of a static/extern SYSCTL
node. This operation should probably be made into a factored out
common macro, hence some device drivers use this. The reason for
changing the SYSCTL API was the need for a SYSCTL parent OID pointer
and not only the SYSCTL parent OID list pointer in order to quickly
generate the sysctl path. The motivation behind this patch is to avoid
parameter loading cludges inside the OFED driver subsystem. Instead of
adding special code to the OFED driver subsystem to post-load tunables
into dynamically created sysctls, we generalize this in the kernel.

Other changes:
- Corrected a possibly incorrect sysctl name from "hw.cbb.intr_mask"
to "hw.pcic.intr_mask".
- Removed redundant TUNABLE statements throughout the kernel.
- Some minor code rewrites in connection to removing not needed
TUNABLE statements.
- Added a missing SYSCTL_DECL().
- Wrapped two very long lines.
- Avoid malloc()/free() inside sysctl string handling, in case it is
called to initialize a sysctl from a tunable, hence malloc()/free() is
not ready when sysctls from the sysctl dataset are registered.
- Bumped FreeBSD version to indicate SYSCTL API change.

MFC after: 2 weeks
Sponsored by: Mellanox Technologies

pcm(4): Permit non-root users to change default unit

Discussed with: mav

Remove "clone manager: " message from verbose dmesg. It is pointless to
print values that are statically hardcoded few lines above that.

Do not handle MOD_SHUTDOWN equally to MOD_UNLOAD in sound kernel module.
MOD_SHUTDOWN is not an end of existence, and there is a life after it.
In particular, code previously called on MOD_SHUTDOWN grabbed lock and
deallocated unit numbering. That caused infinite wait loop if snd_uaudio
tried to destroy its PCM device after that point.

MFC after: 3 days

Make automatic hw.snd.default_unit choice a bit more intelligent. Instead
of just setting it to the first registered device, reevaluate it for each
device registered, trying to choose best candidate, unless one was forced.
For now use such preference order: play&rec, play, rec.

As side effect, this should workaround the situation when HDMI audio output
of the video card, usually not connected to anything, becomes default, that
requires manual user intervention to make sound working. If at some point
this won't be enough, we can try to fetch some additional priority flags
from the device driver.

sysctl(9) cleanup checkpoint: amd64 GENERIC builds cleanly.

Commit the rest of the devices.

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

sound/pcm: use non-const string as a value with SYSCTL_STRING

Although the sysctls are marked with CTLFLAG_RD and the values will stay
immutable, current sysctl implementation stores value pointer in
void* type, which means that const qualifier is discarded anyway
and some newer compilers complaint about that.
We can't use de-const trick in sysctl implementation, because in that
case we could miss an opposite situation where a const value is used
with CTLFLAG_RW sysctl.

Complaint from: gcc 4.4, clang
MFC after: 2 weeks

Sound Mega-commit. Expect further cleanup until code freeze.

For a slightly thorough explaination, please refer to
[1] http://people.freebsd.org/~ariff/SOUND_4.TXT.html .

Summary of changes includes:

1 Volume Per-Channel (vpc). Provides private / standalone volume control
unique per-stream pcm channel without touching master volume / pcm.
Applications can directly use SNDCTL_DSP_[GET|SET][PLAY|REC]VOL, or for
backwards compatibility, SOUND_MIXER_PCM through the opened dsp device
instead of /dev/mixer. Special "bypass" mode is enabled through
/dev/mixer which will automatically detect if the adjustment is made
through /dev/mixer and forward its request to this private volume
controller. Changes to this volume object will not interfere with
other channels.

Requirements:
- SNDCTL_DSP_[GET|SET][PLAY|REC]_VOL are newer ioctls (OSSv4) which
require specific application modifications (preferred).
- No modifications required for using bypass mode, so applications
like mplayer or xmms should work out of the box.

Kernel hints:
- hint.pcm.%d.vpc (0 = disable vpc).

Kernel sysctls:
- hw.snd.vpc_mixer_bypass (default: 1). Enable or disable /dev/mixer
bypass mode.
- hw.snd.vpc_autoreset (default: 1). By default, closing/opening
/dev/dsp will reset the volume back to 0 db gain/attenuation.
Setting this to 0 will preserve its settings across device
closing/opening.
- hw.snd.vpc_reset (default: 0). Panic/reset button to reset all
volume settings back to 0 db.
- hw.snd.vpc_0db (default: 45). 0 db relative to linear mixer value.

2 High quality fixed-point Bandlimited SINC sampling rate converter,
based on Julius O'Smith's Digital Audio Resampling -
http://ccrma.stanford.edu/~jos/resample/. It includes a filter design
script written in awk (the clumsiest joke I've ever written)
- 100% 32bit fixed-point, 64bit accumulator.
- Possibly among the fastest (if not fastest) of its kind.
- Resampling quality is tunable, either runtime or during kernel
compilation (FEEDER_RATE_PRESETS).
- Quality can be further customized during kernel compilation by
defining FEEDER_RATE_PRESETS in /etc/make.conf.

Kernel sysctls:
- hw.snd.feeder_rate_quality.
0 - Zero-order Hold (ZOH). Fastest, bad quality.
1 - Linear Interpolation (LINEAR). Slightly slower than ZOH,
better quality but still does not eliminate aliasing.
2 - (and above) - Sinc Interpolation(SINC). Best quality. SINC
quality always start from 2 and above.

Rough quality comparisons:
- http://people.freebsd.org/~ariff/z_comparison/

3 Bit-perfect mode. Bypasses all feeder/dsp effects. Pure sound will be
directly fed into the hardware.

4 Parametric (compile time) Software Equalizer (Bass/Treble mixer). Can
be customized by defining FEEDER_EQ_PRESETS in /etc/make.conf.

5 Transparent/Adaptive Virtual Channel. Now you don't have to disable
vchans in order to make digital format pass through. It also makes
vchans more dynamic by choosing a better format/rate among all the
concurrent streams, which means that dev.pcm.X.play.vchanformat/rate
becomes sort of optional.

6 Exclusive Stream, with special open() mode O_EXCL. This will "mute"
other concurrent vchan streams and only allow a single channel with
O_EXCL set to keep producing sound.

Other Changes:
* most feeder_* stuffs are compilable in userland. Let's not
speculate whether we should go all out for it (save that for
FreeBSD 16.0-RELEASE).
* kobj signature fixups, thanks to Andriy Gapon <avg@freebsd.org>
* pull out channel mixing logic out of vchan.c and create its own
feeder_mixer for world justice.
* various refactoring here and there, for good or bad.
* activation of few more OSSv4 ioctls() (see [1] above).
* opt_snd.h for possible compile time configuration:
(mostly for debugging purposes, don't try these at home)
SND_DEBUG
SND_DIAGNOSTIC
SND_FEEDER_MULTIFORMAT
SND_FEEDER_FULL_MULTIFORMAT
SND_FEEDER_RATE_HP
SND_PCM_64
SND_OLDSTEREO

Manual page updates are on the way.

Tested by: joel, Olivier SMEDTS <olivier at gid0 d org>, too many
unsung / unnamed heroes.

Slightly adjust copyright text.

Approved by: luigi

Import some new constants and structures fields from OSSv4.
Implement some OSSv4 ioctls to make ossinfo tool work and print
something reasonable.

Add some new oss_sysinfo structure fields from OSSv4.

- Import the HEAD csup code which is the basis for the cvsmode work.

Spelling nit due to my lamenglishness.

Noticed by: brueffer

Add sysctl/tunable "hw.snd.default_auto", which is useful (especially
for non-root users) to automatically assign default unit to a newly
attach device like USB audio.

Reassign default unit to a valid unit, be it during attach or detach.
If nothing is available, set to something that is purely ridiculous
so the next valid attach will notice it.

Tested by: chibis

Last (again ?!?) major commit for RELENG_7, featuring total Giant
eradication in/from userland path, countless locking fixes, etc.

- General sleep call through msleep(9) has been converted to condvar(9)
with better consistencies.
- Heavily guard every possible "slow path" entries (open(), close(),
few ioctl()s, sysctls), but once it entering "fast path" (io, interrupt
started), they are free to fly on their own.
- Rearrange locking sequences, resulting better concurrency and
serialization. Large part doesn't even need locking at all, and will be
removed in future. Less clutter, except in few places due to lock
ordering.
- Anonymous mixer object creation/deletion to simplify mixer handling
beyond typical mixer ioctls.
Submitted by: chibis (with modifications)
- Add few mix_[get|set|..] functions to avoid calling mixer_ioctl()
directly using cryptic arguments.
- Locking fixes to avoid possible deadlock with (still under Giant) USB.
- Better simplex/duplex device handling.
- Recover mmap() functionality for recording, which has been lost
since 2.2.x - 3.x (the introduction of newpcm). Full-duplex mmap still
doesn't work (due to VM/page design), but people still can mmap
both by opening each direction separately. mmaped playback is guarantee
to work either way.
- New sysctl: "hw.snd.compat_linux_mmap" to allow PROT_EXEC page
mapping, due to recent changes in linux compatibility layer which
require it. All linux applications that using sound + mmap() (mostly games)
require this to be enabled. Disabled by default.
- Other goodies.. too many, that will increase releng7 shareholder value
and make users of releng6 (and below) cry ;)

* This commit should be atomic. If anything goes wrong (not counting problem
originated from elsewhere), I will not hesitate to revert everything back
within 12 hours. This substantial changes itself not a rocket science
and the process has begun for almost 2 years, and lots of incremental
changes are already in place during that period of time.
* Some issues does occur in snd_emu10kx (note the 'x') due to various
internal locking issues and it is currently being worked on by chibis.

Tested by: chibis (Yuriy Tsibizov), joel, Alexandre Vieira,
many innocent souls...

Despite several examples in the kernel, the third argument of
sysctl_handle_int is not sizeof the int type you want to export.
The type must always be an int or an unsigned int.

Remove the instances where a sizeof(variable) is passed to stop
people accidently cut and pasting these examples.

In a few places this was sysctl_handle_int was being used on 64 bit
types, which would truncate the value to be exported. In these
cases use sysctl_handle_quad to export them and change the format
to Q so that sysctl(1) can still print them.

Insert NULL pointer checking around devclass_get_maxunit(pcm_devclass, ..) .
Things can get ugly without it due to uninitialized class. RELENG_6 need
a simmilar, but different treatment as well.

err.. perhaps we should teach devclass_get_maxunit() to return -1 ?

MFC after: 1 day

Last major commit and updates for RELENG_7:

- Rework the entire pcm_channel structure:
* Remove rarely used link placeholder, instead, make each pcm_channel
as head/link of each own/each other. Unlock - Lock sequence due to
sleep malloc has been reduced.
* Implement "busy" queue which will contain list of busy/active
channels. This greatly reduce locking contention for example while
servicing interrupt for hardware with many channels or when virtual
channels reach its 256 peak channels.

- So I heard you like v chan ... O RLY?
Welcome to Virtual **Record** Channels (vrec, rec vchans, vchans for
recording, Rec-Chan, you decide), the ultimate solutions for your
nagging O_RDWR full-duplex wannabe (note: flash plugins) monopolizing
single record channel causing EBUSY. Vrec works exactly like Vchans
(or, should I rename it to "Vplay" :) , except that it operates on the
opposite direction (recording). Up to 256 vrecs (like vchans) are
possible.

Notes:
* Relocate dev.pcm.%d.{vchans,vchanformat,vchanrate} to each of its
respective node/direction:
dev.pcm.%d.play.* for "play" (cdev = dsp%d.vp%d)
dev.pcm.%d.rec.* for "record" (cdev = dsp%d.vr%d)
* Don't expect that it will magically give you ability to split
"recording source" (eg: 1 channel for cdrom, 1 channel for mic,
etc). Just admit that you only have a *single* recording source /
channel. Please bug your hardware vendor instead :)

- Bump maxautovchans from 4 to 16. For a full-fledged multimedia
desktop/workstation with too many soundservers installed (esound,
artsd, jackd, pulse/polypaudio, ding-dong pling plong mudkip fuh fuh,
etc), 4 seems inadequate. There will be no memory penalty here, since
virtual channels are allocate only by demand.

- Nuke/Rework the entire statically created cdev entries. Everything is
clonable through snd own clone manager which designed to withstand many
kind of abusive devfs droids such as:
* while : ; do /bin/test -e /dev/dsp ; done
* jot 16777216 0 | while read x ; do ls /dev/dsp0.$x ; done
* hundreds (could be thousands) concurrent threads/process opening
"/dev/dsp" (previously, this might result EBUSY even with just
3 contesting threads/procs).
o Reusable clone objects (instead of creating new one like there's no
tomorrow) after certain expiration deadline. The clone allocator will
decide whether to reuse, share, or creating new clone.
o Automatic garbage collector.

- Dynamic unit magic allocator. Maximum attached soundcards can be tuned
using tunable "hw.snd.maxunit" (Default to 512). Minimum is 16, and
maximum is 2048.

- ..other fixes, mostly related to concurrency issues.

joel@ will do the manpage updates on sound(4).

Have fun.

Spring cleanup on irrelevant NULL checking over M_WAITOK allocations.

Remove NULL allocation checking since malloc() is allow to wait.
(I'll fix other places later..)

- Compile time compatibility for pre/post newbus API (intr filter)
changes. This should ease the job of maintaining codebase since much
of the regression tests are done across os versions.
- bus_setup_intr() -> snd_setup_intr().

o break newbus api: add a new argument of type driver_filter_t to
bus_setup_intr()

o add an int return code to all fast handlers

o retire INTR_FAST/IH_FAST

For more info: http://docs.freebsd.org/cgi/getmsg.cgi?fetch=465712+0+current/freebsd-current

Reviewed by: many
Approved by: re@

Remove dead email address.

Requested by: luigi

Welcome to Once-a-year Sound Mega-Commit. Enjoy numerous updates and fixes
in every sense.

General
-------

- Multichannel safe, endian safe, format safe
* Large part of critical pcm filters such as vchan.c, feeder_rate.c,
feeder_volume.c, feeder_fmt.c and feeder.c has been rewritten so that
using them does not cause the pcm data to be converted to 16bit little
endian.
* Macrosses for accessing pcm data safely are defined within sound.h in
the form of PCM_READ_* / PCM_WRITE_*
* Currently, most of them are probably limited for mono/stereo handling,
but the future addition of true multichannel will be much easier.

- Low latency operation
* Well, this require lot more works to do not just within sound driver,
but we're heading towards right direction. Buffer/block sizing within
channel.c is rewritten to calculate precise allocation for various
combination of sample/data/rate size. As a result, applying correct
SNDCTL_DSP_POLICY value will achive expected latency behaviour simmilar
to what commercial 4front driver do.
* Signal handling fix. ctrl+c of "cat /dev/zero > /dev/dsp" does not
result long delay.
* Eliminate sound truncation if the sound data is too small.
DIY:
1) Download / extract
http://people.freebsd.org/~ariff/lowlatency/shortfiles.tar.gz
2) Do a comparison between "cat state*.au > /dev/dsp" and
"for x in state*.au ; do cat $x > /dev/dsp ; done"
- there should be no "perceivable" differences.
Double close for PR kern/31445.

CAVEAT: Low latency come with (unbearable) price especially for poorly
written applications. Applications that trying to act smarter
by requesting (wrong) blocksize/blockcount will suffer the most.
Fixup samples/patches can be found at:
http://people.freebsd.org/~ariff/ports/

- Switch minimum/maximum sampling rate limit to "1" and "2016000" (48k * 42)
due to closer compatibility with 4front driver.
Discussed with: marcus@ (long time ago?)

- All driver specific sysctls in the form of "hw.snd.pcm%d.*" have been
moved to their own dev sysctl nodes, notably:
hw.snd.pcm%d.vchans -> dev.pcm.%d.vchans
Bump __FreeBSD_version.

Driver specific
---------------

- Ditto for sysctls.

- snd_atiixp, snd_es137x, snd_via8233, snd_hda
* Numerous cleanups and fixes.
* _EXPERIMENTAL_ polling mode support using simple callout_* mechanisme.
This was intended for pure debugging and latency measurement, but proven
good enough in few unexpected and rare cases (such as problematic shared
IRQ with GIANT devices - USB). Polling can be enabled/disabled through
dev.pcm.0.polling. Disabled by default.

- snd_ich
* Fix possible overflow during speed calibration. Delay final
initialization (pcm_setstatus) after calibration finished.
PR: kern/100169
Tested by: Kevin Overman <oberman@es.net>
* Inverted EAPD for few Nec VersaPro.
PR: kern/104715
Submitted by: KAWATA Masahiko <kawata@mta.biglobe.ne.jp>

Thanks to various people, notably Joel Dahl, Yuriy Tsibizov, Kevin Oberman,
those at #freebsd-azalia @ freenode and others for testing.

Joel Dahl will do the manpage update.

MFp4 the sound Google Summer of Code project:

The goal was to sync with the OSSv4 API 4Front Technologies uses in their
proprietary OSS driver. This was successful as far as possible. The part
of the API which is stable is implemented, for the rest there are some
stubs already.

New system ioctls:
- SNDCTL_SYSINFO - obtain audio system info (version, # of audio/midi/
mixer devices, etc.)
- SNDCTL_AUDIOINFO - fetch details about a specific audio device
- SNDCTL_MIXERINFO - fetch details about a specific mixer device

New audio ioctls:
- Sync groups (SNDCTL_DSP_SYNCGROUP/SNDCTL_DSP_SYNCSTART) which allow
triggered playback/recording on multiple devices (even across processes
simultaneously).
- Peak meters (SNDCTL_DSP_GETIPEAKS/SNDCTL_DSP_GETOPEAKS) - can query
audio drivers for peak levels (needs driver support, disabled for now).
- Per channel playback/recording levels -
SNDCTL_DSP_{GET,SET}{PLAY,REC}VOL. Note that these are still in name
only, just wrapping around the AC97-style mixer at the moment. The next
step is to push them down to the drivers.

Audio ioctls still under development by 4Front (for which stubs may exist
in this commit):
- SNDCTL_GETNAME, SNDCTL_{GET,SET}{SONG,LABEL}
- SNDCTL_DSP_{GET,SET}_CHNORDER
- SNDCTL_MIX_ENUMINFO, SNDCTL_MIX_EXTINFO - (might be documented enough in
the OSS releases to work on this. These ioctls cover the cool "twiddle
any knob on your card" features.)

Missing:
- SNDCTL_DSP_COOKEDMODE -- this ioctl is used to give applications direct
access to a card's buffers, bypassing the feeder architecture. It's
a toughy -- "someone" needs to decide :
(a) if this is desireable, and (b) if it's reasonably feasible.

Updates for driver writers:
So far, only two routines to the channel class (in channel_if.m) are added.
One is for fetching a list of discrete supported playback/recording rates
of a channel, and the other is for fetching peak level info (useful for
drawing peak meters). Interested parties may want to help pushing down
SNDCTL_DSP_{GET,SET}{PLAY,REC}VOL into the drivers.

To use the new stuff you need to rebuild the sound drivers or your kernel
(depending on if you use modules or not) and to install soundcard.h (a
buildworld/installworld handles this).

Sponsored by: Google SoC 2006
Submitted by: ryanb
Many thanks to: 4Front Technologies for their cooperation, explanations
and the nice license of their soundcard.h.

Rename some variables. This fixes some (but not all) problems on the way
for WARNS > 2 cleanlyness.

Submitted by: Yuriy Tsibizov <Yuriy.Tsibizov@gfk.ru>

- Rename hw.snd.unit to hw.snd.default_unit to make the purpose more obvious.
- Enable 4 automatic vchan's by default.
- Add some comments which provide ides/questions for improvement.
- Prefix some temporary sysctl's with an underscore to denote that it is not
an official API but a workaround until the real solution is implemented.

MEGA Fixes / Cleanup
--------------------

- Seal the fate of long standing memory leak (4 years, 7 months) during
pcm_unregister(). While destroying cdevs, scan / detect possible
children and free its SLIST placeholder properly.
- Optimize channel allocation / numbering even further. Do brute cyclic
checking only if the channel numbering screwed.
- Mega vchan create/destroy cleanup:
o Implement pcm_setvchans() so everybody can use it freely instead
of implementing their own, be it through sysctl or channel auto
allocation.
o Increase vchan creation/destruction resiliency:
+ it's possible to increase/decrease total vchans even during
busy playback/recording. Busy channel will be left alone, untouched.
Abusive test sample:
# play whatever...
#
while : ; do
sysctl hw.snd.pcm0.vchans=1
sysctl hw.snd.pcm0.vchans=10
sysctl hw.snd.pcm0.vchans=100
sysctl hw.snd.pcm0.vchans=200
done
# Play something else, leave above loop running frantically.
+ Seal another 4 years old bug where it is possible to destroy (virtual)
channel even when its cdevs being referenced by other process.
The "First Come First Served" nature of dsp_clone() is the main
culprit of this issue, and usually manifest itself as dangling
channel <-> process association. Ensure that all of its cdevs
are free from being referenced before destroying it (through
ORPHAN_CDEVT() macross).

All these fixes (including previous fixes) will be MFCed, later.

We shouldn't really care about the return value of mixer_uninit(),
except EBUSY.

Apply more thorough fixes while dealing with device opening and closing:

- Determine open direction using 'flags', not 'mode'. This bug exist since
past 4 years.
- Don't allow opening the same device twice, be it in a same or different
direction.
- O_RDWR is allowed, provided that it is done by a single open (for example
by mixer(8)) and the underlying hardware support true full-duplex operation.
- Do various paranoid checking in case other process/thread trying to hijack
the same device twice (or more).

MFC after: 5 days

Restore CHN_F_BUSY flag which was removed accidentally in previous commit.

Fix severe 8bit integer overflow during channel creation and destruction,
especially for vchans. It turns out that channel numbering always depend
on d->devcount counter (which keep increasing), while PCMMKMINOR() truncate
everything to 8bit length. At some point the truncation cause the newly
created character device overlapped with the existence one, causing erratic
overall system behaviour and panic. Easily reproduce with something like:

(Luckily, only root can reproduce this)

while : ; do
sysctl hw.snd.pcm0.vchans=200
sysctl hw.snd.pcm0.vchans=100
done

- Enforce channel/chardev numbering within 8bit boundary. Return E2BIG
if necessary.
- Traverse d->channels SLIST and try to reclaim "free" counter during channel
creation. Don't rely on d->devcount at all.
- Destroy vchans in reverse order.

Anyway, this is not the fault of vchans. It is just that vchans are so cute
and begging to be abused ;) . Don't blame her.

Old, hidden bugs.. sigh..

MFC after: 3 days

Convert NULL checks into KASSERT (and move them before the first
dereferencing) since a NULL value would be a bug here.

Note: Both affected functions look very similar. A refactoring may
be beneficial.

CID: 483, 485
Found with: Coverity Prevent(tm)
Discussed with: ariff
MFC after: 5 days

sys/dev/sound/pcm/sndstat.c:
* General spl* cleanup. It doesn't serve any purpose anymore.
* Nuke sndstat_busy(). Addition of sndstat_acquire() /
sndstat_release() for sndstat exclusive access. [1]

sys/dev/sound/pcm/sound.c:
* Remove duplicate SLIST_INIT()
* Use sndstat_acquire() / release() to lock / release the entire
sndstat during pcm_unregister(). This should fix LOR #159 [1]

sys/dev/sound/pcm/sound.h:
* Definition of SD_F_SOFTVOL (part of feeder volume)
* Nuke sndstat_busy(). Addition of sndstat_acquire() /
sndstat_release() for exclusive sndstat access. [1]

Submitted by: Ariff Abdullah <skywizard@MyBSD.org.my>
LOR: 159 [1]
Discussed with: yongari [1]

- Fix the locking in dsp.c to prevent a LOR (AFAIK not on the LOR page).

- Remove an assertion in sound.c, it's not needed (and causes a panic now).
From the conversation via mail between glebius and Ariff:
---snip---
> Well, but which mutex protects now? Do we own anything else
> in pcm_chnalloc()? I see some queue(4) macros in pcm_chnalloc(),
> they should be protected, shouldn't they?
Queue insertion/removal occur during
1) driver loading (which is pretty much single thread /
sequential) or unloading (mutex protected, bail out if there is
any channel with refcount > 0 or busy).
2) vchan_create()/destroy(), (which is *sigh* quite complicated), but
somehow protected by 'master'/parent channel mutex. Other
thread cannot add/remove vchan (or even continue traversing
that queue) unless it can acquire parent channel mutex.
---snip---

Fix the locking in dsp.c to prevent a LOR (AFAIK not on the LOR page).

Submitted by: Ariff Abdullah <skywizard@MyBSD.org.my>
Tested with: INVARIANTS[1] and DIAGNOSTICS[2]
Tested by: netchild [1,2], David Reid <david@jetnet.co.uk> [1]

- channel.h
* New definition CHN_F_HAS_VCHAN.
- channel.c
* Use CHN_F_HAS_VCHAN to mark channel with vchan capability instead
of relying on SLIST_EMPTY(&channel->children) == true for better
clarification and future possible usages of children (like
'slave' channel).
* Various fixes, including blocksize / format bps allignment,
better 24bit seeking (mplayer, others).
* Improve format chain building, it's now possible to record something
to a format non-native to the soundcard through various feeder format
converters or to higher sampling rate. This also gains another feature,
like doing vchan mixing on non s16le soundcard such as sb8.
- sound.c
* Increase robustness within various function that handle vchan
creation / termination (these function need a total rewrite, but
that would cause other major rewrite within various places too!).
As far as its robustness can be guaranteed, leave it as is.
* Optimize channel ordering, prefer *real* hardware playback
channels over virtual channels. cat /dev/sndstat should look
better.
* Increase sndstat verbosity to include bufsoft/bufhard allocation.
- vchan.c
* Fix LOR 119.
- http://sources.zabbadoz.net/freebsd/lor.html#119
* Reorder / increase robustness of vchan_create() / destroy().
Enforce destroy_dev() during destroy operation, fix possible
panic / dangling character device.
- http://lists.freebsd.org/pipermail/freebsd-current/2005-May/050308.html
* Tolerate a little bit more during mixing process, this should help
non s16le soundcards.

Note: Recoring in a non-native rate/format may result in overruns. A friendly
application is wavrec from audio/wavplay. The problem is under
investigation.

Submitted by: Ariff Abdullah <skywizard@MyBSD.org.my>

* Fix panic during driver unload on second attempt after failure on
first (device busy).
* Fix module unloading for sound.ko itself.

Submitted by: Ariff Abdullah <skywizard@MyBSD.org.my>
Tested by: multimedia@

Start each of the license/copyright comments with /*-, minor shuffle of lines

Rename the sound device drivers:

- `sound'
The generic sound driver, always required.

- `snd_*'
Device-dependent drivers, named after the sound module names.
Configure accordingly to your hardware.

In addition, rename the `snd_pcm' module to `sound' in order to sync
with the driver names.

Suggested by: cg

Nuke a cryptic and useless diagnostic printf().

Create a new mutex type for virtual channels. This allows us to get
rid of the MTX_DUPOK flag on channel mutexes, which allows witness to
do a better job of lock order checking. Nuke snd_chnmtxcreate() since
it is no longer needed.

Tested by: matk

Change KASSERT() in feed_vchan16() into an explicit test and call to
panic() so that the buffer overflow just beyond this point is always
caught, even when the code is not compiled with INVARIANTS.

Change chn_setblocksize() buffer reallocation code to attempt to avoid
the feed_vchan16() buffer overflow by attempting to always keep the
bufsoft buffer at least as large as the bufhard buffer.

Print a diagnositic message
Danger! %s bufsoft size increasing from %d to %d after CHANNEL_SETBLOCKSIZE()
if our best attempts fail. If feed_vchan16() were to be called by
the interrupt handler while locks are dropped in chn_setblocksize()
to increase the size bufsoft to match the size of bufhard, the panic()
code in feed_vchan16() will be triggered. If the diagnostic message
is printed, it is a warning that a panic is possible if the system
were to see events in an "unlucky" order.

Change the locking code to avoid the need for MTX_RECURSIVE mutexes.

Add the MTX_DUPOK option to the channel mutexes and change the locking
sequence to always lock the parent channel before its children to avoid
the possibility of deadlock.

Actually implement locking assertions for the channel mutexes and fix
the problems found by the resulting assertion violations.

Clean up the locking code in dsp_ioctl().

Allocate the channel buffers using the malloc() M_WAITOK option instead
of M_NOWAIT so that buffer allocation won't fail. Drop locks across
the malloc() calls.

Add/modify KASSERTS() in attempt to detect problems early.

Abuse layering by adding a pointer to the snd_dbuf structure that points
back to the pcm_channel that owns it. This allows sndbuf_resize() to do
proper locking without having to change the its API, which is used by
the hardware drivers.

Don't dereference a NULL pointer when setting hw.snd.maxautovchans
if a hardware driver is not loaded. Noticed by Ryan Sommers
<ryans at gamersimpact.com>.

Tested by: Stefan Ehmann <shoesoft AT gmx.net>
Tested by: matk (Mathew Kanner)
Tested by: Gordon Bergling <gbergling AT 0xfce3.net>

Fix a panic when kldloading a sound driver. Do this by replacing the
link-list of dev_t's with named variables. Remove used code.

Approved by: tanimura (mentor)

As previously announced: discontinue use of makedev() call in soundcode.

This takes us a lot closer to refcounting dev_t.

This patch originally by cg@ with a few minor changes by me.

It is largely untested, but has been HEADSUP'ed twice, so presumably
people have not found any issues with it.

Submitted by: cg@

The last argument to mtx_init() should be MTX_DEF, not 0. This is not a
functional change since MTX_DEF happens to be defined as 0.

update my email address.

handle locking when creating or destroying vchans better

Back out M_* changes, per decision of the TRB.

Approved by: trb

Remove M_TRYWAIT/M_WAITOK/M_WAIT. Callers should use 0.
Merge M_NOWAIT/M_DONTWAIT into a single flag M_NOWAIT.

Don't call destroy_dev it a channel has children.
vchan creation doesn't lead to /dev entry creation if the new vchan is the
first child of a channel,
This fix a panic that happens when loading a sound driver module, creating
vchans and unloading the driver.

Approved by: cg
MFC after: 3 days

(hopefully) fix build breakage some people are seeing

Approved by: re

various fixes to eliminate locking warnings

Approved by: re
Reviewed by: orion

Call pcm_chn_destroy() in pcm_killchan() so that channel mutexes are destroyed and struct pcm_channel freed.

Reviewed by: cg
MFC after: 3 days

Be sure to unregister from sndstat on unregister. Gets rid of phantom
sndstat output after removing uaudio.

Fix some of the places where sound(4) can sleep with a lock held. (Help
courtesy of fenner).

Fix the sound driver vchan support to work when hw.snd.maxautovchans
has been specified through /boot/loader.conf as opposed to setting it
in /etc/sysctl.conf. Only PCMDIR_PLAY channel can be used as a parent
of virtual channel. Do not initialize a new vchan for a given physical
channel if other physical channel already has one created.

PR: 31597
Approved by: obrien (mentor)

Move lock in pcm_chn_add() to after malloc.

PR: kern/40157
Submitted by: Dan Lukes <dan@obluda.cz>

Try and solve some cases of labels at end of compound statements that gcc
now objects to (as it should, it is not legal C).

add a missing \n to an unregister failure message

Change snd_mtxcreate() to accept a lock type as an extra argument that is
passed to mtx_init().

* improve error handling
* be more specific in verbose boot messages
* allow the feeder subsystem to veto pcm* attaching if there is an error
initialising the root feeder
* don't free/malloc a new tmpbuf when resizing a snd_dbuf to the same size as
it currently is
* store the feeder description in the feeder structure instead of mallocing
space for it

Fix code that had rotted behind debugging macros.

Approved by: cg (in principle)
MFC after: 2 weeks

improve sndstat output of feederchains so it can be understood without
reading the feeder sourcecode

print warnings if a pcm*.buffersize hint is out of range or a non-power-of-2

change tracking of channel counts.

add method for retrieving "buffersize" hints for pcm devices, adjusted for
specified minimum, maximum and default values.

- Correctly increment the channel refcount in dsp_open() such that it is
no longer possible to unload the driver module while sound is playing
(which resulted in a panic).
- Fix a similar problem with the sndstat device that I found while looking
at the above.
- Append a newline character to error messages in pcm_unregister()

Reviewed by: cg
MFC after: 10 days

add a method for recording of specific channels for devices with more than
one hardware record channel. new devices, /dev/dsprX.Y where X is unit
number and Y is channel index.

tweaks to reduce latency/pauses in output

add some extra diagnostic info to sndstat output.

many changes:

* add new channels to the end of the list so channels used in order of
addition

* de-globalise definition of struct snddev_info and provide accessor
functions where necessary.

* move the $FreeBSD$ tag in each .c file into a macro and allow the
/dev/sndstat handler to display these when set to maximum verbosity to aid
debugging.

* allow each device to register its own sndstat handler to reduce the amount
of groping sndstat must do in foreign structs.

remove obsolete typedefs.

only define INTR_TYPE_AV if it is not already defined.

Correct obviously wrong mistakes.

make it compile again in -current

Make all this compile on 4.3, modulus sbuf.

don't flag the playback hardchan as busy on devices with only one of them.

if a device has vchans already but they are all busy, allocate another one
at open() time, up to a maximum of hw.snd.maxvchans.

when creating/destroying vchans, don't make/remove a devnode for the
first/last one as it replaces a hardchan.

add a tunable/sysctl, hw.snd.autovchans. if this is set to a value n where
n > 0, n vchans will be assigned to any devices that subsequently register
with a single playback channel.

add defines and ifdefs so this code will compile on 4.x

add spls so this code will work on 4.x

use devclass_get_maxunit() correctly

revise dsp_clone() to return the first nonbusy channel instead of simply
cycling channel numbers.

remove unused fields from struct snddev_info.

Use INTR_TYPE_AV for the interrupt handlers because:
1: most drivers are sensitive to timing, and
2: the handlers are MPSAFE and need a chance to get into the kernel
before some other non-mpsafe handler blocks the ithread on Giant in
shared irq cases.

Reviewed by: cg (in principle)

use a global devclass for all drivers - i'm not entirely sure why this
worked before.

mixer, dsp and sndstat are seperate devices - give them their own cdevsws
instead of demuxing requests sent to a single cdevsw.

use the si_drv1/si_drv2 fields in dev_t structures for holding information
specific to an open instance of mixer/dsp.

nuke /dev/{dsp,dspW,audio}[0-9]* links - this functionality is now provided
using cloning.

various locking fixes.

various locking fixes, rework open logic and channel registration

PR: kern/28084

sbuf_new(9) now returns a struct sbuf * instead of an int. If the caller
does not provide a struct sbuf, sbuf_new(9) will allocate one and return
a pointer to it.

"Fix" the previous initial attempt at fixing TUNABLE_INT(). This time
around, use a common function for looking up and extracting the tunables
from the kernel environment. This saves duplicating the same function
over and over again. This way typically has an overhead of 8 bytes + the
path string, versus about 26 bytes + the path string.

lock sound device when adding/removing channels
implement setblocksize for vchans
don't panic when doing certain ioctls or aborting on a vchan
xmms now works with vchans

Back out part of my previous commit. This was a last minute change
and I botched testing. This is a perfect example of how NOT to do
this sort of thing. :-(

Make the TUNABLE_*() macros look and behave more consistantly like the
SYSCTL_*() macros. TUNABLE_INT_DECL() was an odd name because it didn't
actually declare the int, which is what the name suggests it would do.

beginnings of virtual playback channel support

instead of using two malloced arrays for storing channel lists, use an
slist. convert the sndstat device to use sbufs and optionally provide more
detail about channel state.

vchans are software mixed playback channels. they are not enabled by this
commit. they use the feeder infrastructure to emulate normal playback
channels in a manner transparent to applications, whilst providing as many
channels are desired, especially suitable for devices with only one hardware
playback channel. in the future they will provide additional features.

those wishing to test this functionality will need to add vchan.c to
sys/conf/files and use 'sysctl -w hw.snd.pcm0.vchans' to enable it.

blocksize and auto-rate selection are not yet supported.

Send the remains (such as I have located) of "block major numbers" to
the bit-bucket.

mega-commit.

this introduces a new buffering mechanism which results in dramatic
simplification of the channel manager.

as several structures have changed, we take the opportunity to move their
definitions into the source files where they are used, make them private and
de-typedef them.

the sound drivers are updated to use snd_setup_intr instead of
bus_setup_intr, and to comply with the de-typedefed structures.

the ac97, mixer and channel layers have been updated with finegrained
locking, as have some drivers- not all though. the rest will follow soon.

don't leak memory allocated for feeders at module unload
kill the fake channel when unregistering

fix a panic triggerable by anyone with read/write access to the audio
devices. opening /dev/{dsp,dspW,audio}0 and then opening a different device
from that list and closing it resulted in a panic when any operation is
performed on the first fd.

we prevent this happening by denying the second open unless it uses the same
minor device as the first.

PR: kern/25519

nuke the splstack stuff, snd_mtx* will now be no-ops on 4.x

add functions for sound drivers to use for locking and setting up interrupt
handlers. these are not yet used, but will allow compatibility for driver
modules from 5.x to 4.x.

MFS: 4.x/5.x compatibility #ifdefs

Woops, use the SYSCTL_STATIC_CHILDREN() macro instead of manually
expanding it for _hw_snd.

- Make the 'hwvol_mixer' and 'hwvol_step' variables be specific to a
specific snd_mixer device rather than global across all mixers.
- Add per-mixer mute status and saved mute_level so that the mixer_hwmute()
function can now toggle the mute state when the mute button is pressed.
- Create a dynamic sysctl tree hw.snd.pcmX when a pcm device is registered.
- Move the hw.snd.hwvol_* sysctl's to hw.snd.pcmX.hwvol_* so that they
are now properly device-specific. Eventually when the mixers become
their own devices these sysctl's will move to live under a mixerX tree.
- Change the interface of the hwvol_mixer sysctl so that it reports the
name of the current mixer device instead of the number and is settable
with the name instead of the number.
- Add a new function mixer_hwinit() used to setup the dynamic sysctl's
needed for the hwvol support that can be called by drivers that support
hwvol.

Reviewed by: cg

The 'maxchans' count is one more than the number of channels, so
'chancount' never got up to equaling 'maxchans'. As a result,
pcm_makelinks() was never called, and one always had to set the sysctl to
get the /dev/mixer and other symlinks generated in the DEVFS case. Instead,
change the test in pcm_addchan() to call pcm_makelinks() after the first
channel is initialized, since the aliases are linked to channel 0.

Reviewed by: cg

Rename the loader tunable from hw.sndunit to hw.snd.unit.

Submitted by: cg

Create a new sysctl node 'hw.snd' and move 'hw.sndunit' to
'hw.snd.unit'.

Reviewed by: cg

kobjify.

this gives us several benefits, including:

* easier extensibility- new optional methods can be added to
ac97/mixer/channel classes without having to fixup every driver.

* forward compatibility for drivers, provided no new mandatory methods are
added.

be more verbose about failed unload attempts

update for phk's last devfs commit

change mixer api slightly
change channel interface - kobj implementation coming soonish
make pcm_makelinks not panic if modular
add pcm_unregister()

these changes support newpcm kld unloading, but this is only implemented
by ds1.c

add devfs support. when devfs is enabled, sysctl hw.sndunit is used to set
which sound unit the /dev/{dsp,mixer,dspW,audio} links point at. this can
also be set from the loader.

add module metadata. this is a hack, sound drivers will eventually present a
bus to which pcm, mixer, etc will attach.

fix a bug where opening for write would not fail if channel allocation failed

when playing, if we stall for 1s with no data advancing, abort and mark the
channel dead - fail all future operations

don't panic if we try to add a channel we said we wouldn't

if a device has no play or no record channels, set its simplex flag.

duh, i forgot to change a bitmask, sorry alexander

Submitted by: Alexander Matey <matey@cis.ohio-state.edu>

fix minor numbers for multi-channel devices

Submitted by: Alexander Matey <matey@cis.ohio-state.edu>

allow /dev/dsp to be opened seperately for reading and writing.

update the ac97 layer:
* add a callback for initialising the mixer interface
* support ac97 2.1 variable rate audio feature

fix ac97-using drivers for the above

add suspend/resume support for neomagic

fix missing \n in sndstat output

modify sndstat output

allow mixer-only devices - ie, devices with no play/rec channels

don't panic if channel init fails, report and fail gracefully

allow (broken) apps to use mixer ioctls on dsp devices. eg: vmware

Submitted by: "Vladimir N. Silyaev" <vsilyaev@mindspring.com>

move make_dev operations for audio channels to pcm_addchan(). in theory,
with modifications to MAKEDEV this will allow use of multiple output streams
on cards supporting it, eg trident 4dwave.

move channel-swapping support to the hardware driver since it knows the card
state best

Update for pnp adjustments regarding NPNP.

Also, optimize out a mess of #if's that were duplicating work already
done by config(8). For example, if a file is marked as
"dev/sound/pci/foo.c optional pcm pci" then it's only added if pcm *and*
pci are present, so #if NPCM > 0 and #if NPCI > 0 are totally redundant.
A bit more work is still needed.

Discussed with: cg (a few weeks ago)

fix dma underrun issues
mutate some panics to kasserts
add more spl protection

PR: kern/14990
Partially Submitted by: Vladimir N.Silyaev <vns@delta.odessa.ua>
Reviewed by: dfr

repo-copied to make way for newmidi, this commit updates include paths

The unit of sndstat is fixed to zero.

Fix for multiple pcm devices.

Call make_dev() to shut up the warning.

Pointed out by: Donn Miller <dmmiller@cvzoom.net>

* add a non-reset device- will not reset the channel on open. you
will have to mknod yourself for now.
* don't eat the first write()
* partial rvplayer fix- don't panic on unaligned writes unless our
feeder chain requires them for downconversion. a fuller fix is
on the way.

Remove five now unused fields from struct cdevsw. They should never
have been there in the first place. A GENERIC kernel shrinks almost 1k.

Add a slightly different safetybelt under nostop for tty drivers.

Add some missing FreeBSD tags

$Id$ -> $FreeBSD$

say hello to newpcm. it is not yet enabled, requiring new pnp code from dfr
to compile successfully. further details will be provided in the commit
enabling newpcm.