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: 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: 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: Remove obsolete chn_setvolume()

It is marked as obsolete and there are no consumers of it anymore.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Reviewed by: markj, emaste
Differential Revision: https://reviews.freebsd.org/D44853

sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

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

sound(4): Implement mixer mute control for feeder channels.

PR: 258711
Differential Revision: https://reviews.freebsd.org/D31636
MFC after: 1 week
Sponsored by: NVIDIA Networking

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

Decrease the default audio playback latency to a maximum of 21.3ms.
This significantly improves the audio playback response time.

Discussed with: mav@
MFC after: 1 week
Sponsored by: Mellanox Technologies

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.

Extend the maximum number of allowed PCM channels in a PCM stream to
127 and decrease the maximum number of sub-channels to 1. These
definitions are only used inside the kernel and can be changed later
if more than one sub-channel is desired. This has been done to allow
so-called USB audio rack modules to work with FreeBSD.

Bump the FreeBSD version to force recompiling all external modules.

MFC after: 2 weeks
Reviewed by: mav

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

Remove custom KOBJMETHOD(), CHANNEL_DECLARE() and MIXER_DECLARE()
(enabled with SND_DEBUG) that was intended to provoke build failure
due to inconsistencies.

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.

Bring in USB4BSD, Hans Petter Selasky rework of the USB stack
that includes significant features and SMP safety.

This commit includes a more or less complete rewrite of the *BSD USB
stack, including Host Controller and Device Controller drivers and
updating all existing USB drivers to use the new USB API:

1) A brief feature list:

- A new and mutex enabled USB API.

- Many USB drivers are now running Giant free.

- Linux USB kernel compatibility layer.

- New UGEN backend and libusb library, finally solves the "driver
unloading" problem. The new BSD licensed libusb20 library is fully
compatible with libusb-0.1.12 from sourceforge.

- New "usbconfig" utility, for easy configuration of USB.

- Full support for Split transactions, which means you can use your
full speed USB audio device on a high speed USB HUB.

- Full support for HS ISOC transactions, which makes writing drivers
for various HS webcams possible, for example.

- Full support for USB on embedded platforms, mostly cache flushing
and buffer invalidating stuff.

- Safer parsing of USB descriptors.

- Autodetect of annoying USB install disks.

- Support for USB device side mode, also called USB gadget mode,
using the same API like the USB host side. In other words the new
USB stack is symmetric with regard to host and device side.

- Support for USB transfers like I/O vectors, means more throughput
and less interrupts.

- ... see the FreeBSD quarterly status reports under "USB project"

2) To enable the driver in the default kernel build:

2.a) Remove all existing USB device options from your kernel config
file.

2.b) Add the following USB device options to your kernel configuration
file:

# USB core support
device usb2_core

# USB controller support
device usb2_controller
device usb2_controller_ehci
device usb2_controller_ohci
device usb2_controller_uhci

# USB mass storage support
device usb2_storage
device usb2_storage_mass

# USB ethernet support, requires miibus
device usb2_ethernet
device usb2_ethernet_aue
device usb2_ethernet_axe
device usb2_ethernet_cdce
device usb2_ethernet_cue
device usb2_ethernet_kue
device usb2_ethernet_rue
device usb2_ethernet_dav

# USB wireless LAN support
device usb2_wlan
device usb2_wlan_rum
device usb2_wlan_ral
device usb2_wlan_zyd

# USB serial device support
device usb2_serial
device usb2_serial_ark
device usb2_serial_bsa
device usb2_serial_bser
device usb2_serial_chcom
device usb2_serial_cycom
device usb2_serial_foma
device usb2_serial_ftdi
device usb2_serial_gensa
device usb2_serial_ipaq
device usb2_serial_lpt
device usb2_serial_mct
device usb2_serial_modem
device usb2_serial_moscom
device usb2_serial_plcom
device usb2_serial_visor
device usb2_serial_vscom

# USB bluetooth support
device usb2_bluetooth
device usb2_bluetooth_ng

# USB input device support
device usb2_input
device usb2_input_hid
device usb2_input_kbd
device usb2_input_ms

# USB sound and MIDI device support
device usb2_sound

2) To enable the driver at runtime:

2.a) Unload all existing USB modules. If USB is compiled into the
kernel then you might have to build a new kernel.

2.b) Load the "usb2_xxx.ko" modules under /boot/kernel having the same
base name like the kernel device option.

Submitted by: Hans Petter Selasky hselasky at c2i dot net
Reviewed by: imp, alfred

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

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...

Filter/compress the amount of channel trigger. This should reduce
much of lock/unlock contentions within the interrupt handler. Most
of these drivers only need PCMTRIG_START or STOP (ABORT).

Discussed with: scottl

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.

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.

- 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>

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

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>

update my email address.

(hopefully) fix build breakage some people are seeing

Approved by: re

Fix code that had rotted behind debugging macros.

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

add a tunable/sysctl, hw.snd.targetirqrate, to modify the default target
irq rate for apps that do not set a blocksize.

KSE Milestone 2
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after: ha ha ha ha

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.

add some extra diagnostic info to sndstat output.

remove obsolete typedefs.

only define INTR_TYPE_AV if it is not already defined.

Make all this compile on 4.3, modulus sbuf.

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

add spls so this code will work on 4.x

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.

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.

update code dealing with snd_dbuf objects to do so using a functional interface

modify chn_setblocksize() to pick a default soft-blocksize appropriate to the
sample rate and format in use. it will aim for a power of two size small
enough to generate block sizes of at most 20ms. it will also set the
hard-blocksize taking into account rate/format conversions in use.

update drivers to implement setblocksize correctly:
updated, tested: sb16, emu10k1, maestro, solo
updated, untested: ad1816, ess, mss, sb8, csa
not updated: ds1, es137x, fm801, neomagic, t4dwave, via82c686

i lack hardware to test: ad1816, csa, fm801, neomagic
others will be updated/tested in the next few days.

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.

add reinit functions to mixers
unstaticize chn_start()
add reset/resetdone functions to channels

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

rework feeder sytem to allow feeders in klds

modify driver capability reporting format to list every audio format
seperately- required for above and because we could not previously indicate
that mono was unsupported.

there should be no functional impact.

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

handle emulated dma reads

don't try to get sample size from snd_dbuf

implement settrigger according to spec

fixes for non-blocking mode

more mmap fixes

make mmap sort-of work. there seem to be interactions with certain hw
drivers, so still work in progress.

do various mmap-related ioctls right.

improve blocksize control.

bits of cleanup.

try increasing 2ndbuffer size to 64k

- latest 2ndbuffer patch
- make chn_setdir work for rec on isa cards
- note: es1371 does not irq in smp

Submitted by: tanimura

more dma underrun fixes, using a per-channel 2nd buffer

Submitted by: tanimura

* 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.

$Id$ -> $FreeBSD$

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.