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.

1 files changed, 19 insertions, 1 deletions

diff --git a/sys/dev/sound/midi/midi.c b/sys/dev/sound/midi/midi.c
index b6ac879..59ea141 100644
--- a/sys/dev/sound/midi/midi.c
+++ b/sys/dev/sound/midi/midi.c
@@ -58,8 +58,23 @@ __FBSDID("$FreeBSD$");
 #include <sys/poll.h>
 #include <sys/sbuf.h>
 #include <sys/kobj.h>
+#ifdef SND_DEBUG
+#undef KOBJMETHOD
+#define KOBJMETHOD(NAME, FUNC)						\
+	{								\
+		&NAME##_desc,						\
+		(kobjop_t) ((FUNC != (NAME##_t *)NULL) ? FUNC : NULL)	\
+	}
+#endif
+#ifndef KOBJMETHOD_END
+#define KOBJMETHOD_END	{ NULL, NULL }
+#endif
 #include <sys/module.h>
 
+#ifdef HAVE_KERNEL_OPTION_HEADERS
+#include "opt_snd.h"
+#endif
+
 #include <dev/sound/midi/midi.h>
 #include "mpu_if.h"
 
@@ -145,7 +160,7 @@ static kobj_method_t midisynth_methods[] = {
 	KOBJMETHOD(synth_alloc, midisynth_alloc),
 	KOBJMETHOD(synth_controller, midisynth_controller),
 	KOBJMETHOD(synth_bender, midisynth_bender),
-	{0, 0}
+	KOBJMETHOD_END
 };
 
 DEFINE_CLASS(midisynth, midisynth_methods, 0);
@@ -1367,6 +1382,7 @@ midi_destroy(struct snd_midi *m, int midiuninit)
 
 	MIDI_DEBUG(3, printf("midi_destroy\n"));
 	m->dev->si_drv1 = NULL;
+	mtx_unlock(&m->lock);	/* XXX */
 	destroy_dev(m->dev);
 	TAILQ_REMOVE(&midi_devs, m, link);
 	if (midiuninit)
@@ -1418,6 +1434,8 @@ midi_unload()
 			goto exit1;
 	}
 
+	mtx_unlock(&midistat_lock);	/* XXX */
+
 	destroy_dev(midistat_dev);
 	/*
 	 * Made it here then unload is complete