path: root/lib/libsndio/sio_sun.c

/*	$OpenBSD: sio_sun.c,v 1.17 2015/10/02 09:40:57 ratchov Exp $	*/
/*
 * Copyright (c) 2008 Alexandre Ratchov <alex@caoua.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/audioio.h>
#include <sys/stat.h>

#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "debug.h"
#include "sio_priv.h"

#define DEVPATH_PREFIX	"/dev/audio"
struct sio_sun_hdl {
	struct sio_hdl sio;
	int fd;
	int filling;
	unsigned int ibpf, obpf;	/* bytes per frame */
	unsigned int ibytes, obytes;	/* bytes the hw transferred */
	unsigned int ierr, oerr;	/* frames the hw dropped */
	int idelta, odelta;		/* position reported to client */
};

static void sio_sun_close(struct sio_hdl *);
static int sio_sun_start(struct sio_hdl *);
static int sio_sun_stop(struct sio_hdl *);
static int sio_sun_setpar(struct sio_hdl *, struct sio_par *);
static int sio_sun_getpar(struct sio_hdl *, struct sio_par *);
static int sio_sun_getcap(struct sio_hdl *, struct sio_cap *);
static size_t sio_sun_read(struct sio_hdl *, void *, size_t);
static size_t sio_sun_write(struct sio_hdl *, const void *, size_t);
static int sio_sun_nfds(struct sio_hdl *);
static int sio_sun_pollfd(struct sio_hdl *, struct pollfd *, int);
static int sio_sun_revents(struct sio_hdl *, struct pollfd *);

static struct sio_ops sio_sun_ops = {
	sio_sun_close,
	sio_sun_setpar,
	sio_sun_getpar,
	sio_sun_getcap,
	sio_sun_write,
	sio_sun_read,
	sio_sun_start,
	sio_sun_stop,
	sio_sun_nfds,
	sio_sun_pollfd,
	sio_sun_revents,
	NULL, /* setvol */
	NULL, /* getvol */
};

/*
 * convert sun encoding to sio_par encoding
 */
static int
sio_sun_infotoenc(struct sio_sun_hdl *hdl, struct audio_prinfo *ai,
    struct sio_par *par)
{
	par->msb = ai->msb;
	par->bits = ai->precision;
	par->bps = ai->bps;
	switch (ai->encoding) {
	case AUDIO_ENCODING_SLINEAR_LE:
		par->le = 1;
		par->sig = 1;
		break;
	case AUDIO_ENCODING_SLINEAR_BE:
		par->le = 0;
		par->sig = 1;
		break;
	case AUDIO_ENCODING_ULINEAR_LE:
		par->le = 1;
		par->sig = 0;
		break;
	case AUDIO_ENCODING_ULINEAR_BE:
		par->le = 0;
		par->sig = 0;
		break;
	case AUDIO_ENCODING_SLINEAR:
		par->le = SIO_LE_NATIVE;
		par->sig = 1;
		break;
	case AUDIO_ENCODING_ULINEAR:
		par->le = SIO_LE_NATIVE;
		par->sig = 0;
		break;
	default:
		DPRINTF("sio_sun_infotoenc: unsupported encoding\n");
		hdl->sio.eof = 1;
		return 0;
	}
	return 1;
}

/*
 * convert sio_par encoding to sun encoding
 */
static void
sio_sun_enctoinfo(struct sio_sun_hdl *hdl,
    unsigned int *renc, struct sio_par *par)
{
	if (par->le == ~0U && par->sig == ~0U) {
		*renc = ~0U;
	} else if (par->le == ~0U || par->sig == ~0U) {
		*renc = AUDIO_ENCODING_SLINEAR;
	} else if (par->le && par->sig) {
		*renc = AUDIO_ENCODING_SLINEAR_LE;
	} else if (!par->le && par->sig) {
		*renc = AUDIO_ENCODING_SLINEAR_BE;
	} else if (par->le && !par->sig) {
		*renc = AUDIO_ENCODING_ULINEAR_LE;
	} else {
		*renc = AUDIO_ENCODING_ULINEAR_BE;
	}
}

/*
 * try to set the device to the given parameters and check that the
 * device can use them; return 1 on success, 0 on failure or error
 */
static int
sio_sun_tryinfo(struct sio_sun_hdl *hdl, struct sio_enc *enc,
    unsigned int pchan, unsigned int rchan, unsigned int rate)
{
	struct audio_info aui;
	struct audio_prinfo *pr;

	pr = (hdl->sio.mode & SIO_PLAY) ? &aui.play : &aui.record;

	AUDIO_INITINFO(&aui);
	if (enc) {
		if (enc->le && enc->sig) {
			pr->encoding = AUDIO_ENCODING_SLINEAR_LE;
		} else if (!enc->le && enc->sig) {
			pr->encoding = AUDIO_ENCODING_SLINEAR_BE;
		} else if (enc->le && !enc->sig) {
			pr->encoding = AUDIO_ENCODING_ULINEAR_LE;
		} else {
			pr->encoding = AUDIO_ENCODING_ULINEAR_BE;
		}
		pr->precision = enc->bits;
	}
	if (rate)
		pr->sample_rate = rate;
	if ((hdl->sio.mode & (SIO_PLAY | SIO_REC)) == (SIO_PLAY | SIO_REC))
		aui.record = aui.play;
	if (pchan && (hdl->sio.mode & SIO_PLAY))
		aui.play.channels = pchan;
	if (rchan && (hdl->sio.mode & SIO_REC))
		aui.record.channels = rchan;
	if (ioctl(hdl->fd, AUDIO_SETINFO, &aui) < 0) {
		if (errno == EINVAL)
			return 0;
		DPERROR("sio_sun_tryinfo: setinfo");
		hdl->sio.eof = 1;
		return 0;
	}
	if (ioctl(hdl->fd, AUDIO_GETINFO, &aui) < 0) {
		DPERROR("sio_sun_tryinfo: getinfo");
		hdl->sio.eof = 1;
		return 0;
	}
	if (pchan && aui.play.channels != pchan)
		return 0;
	if (rchan && aui.record.channels != rchan)
		return 0;
	if (rate) {
		if ((hdl->sio.mode & SIO_PLAY) &&
		    (aui.play.sample_rate != rate))
			return 0;
		if ((hdl->sio.mode & SIO_REC) &&
		    (aui.record.sample_rate != rate))
			return 0;
	}
	return 1;
}

/*
 * guess device capabilities
 */
static int
sio_sun_getcap(struct sio_hdl *sh, struct sio_cap *cap)
{
#define NCHANS (sizeof(chans) / sizeof(chans[0]))
#define NRATES (sizeof(rates) / sizeof(rates[0]))
	static unsigned int chans[] = {
		1, 2, 4, 6, 8, 10, 12
	};
	static unsigned int rates[] = {
		8000, 11025, 12000, 16000, 22050, 24000,
		32000, 44100, 48000, 64000, 88200, 96000
	};
	struct sio_sun_hdl *hdl = (struct sio_sun_hdl *)sh;
	struct sio_par savepar;
	struct audio_encoding ae;
	unsigned int nenc = 0, nconf = 0;
	unsigned int enc_map = 0, rchan_map = 0, pchan_map = 0, rate_map;
	unsigned int i, j, conf;

	if (!sio_sun_getpar(&hdl->sio, &savepar))
		return 0;

	/*
	 * fill encoding list
	 */
	for (ae.index = 0; nenc < SIO_NENC; ae.index++) {
		if (ioctl(hdl->fd, AUDIO_GETENC, &ae) < 0) {
			if (errno == EINVAL)
				break;
			DPERROR("sio_sun_getcap: getenc");
			hdl->sio.eof = 1;
			return 0;
		}
		if (ae.flags & AUDIO_ENCODINGFLAG_EMULATED)
			continue;
		if (ae.encoding == AUDIO_ENCODING_SLINEAR_LE) {
			cap->enc[nenc].le = 1;
			cap->enc[nenc].sig = 1;
		} else if (ae.encoding == AUDIO_ENCODING_SLINEAR_BE) {
			cap->enc[nenc].le = 0;
			cap->enc[nenc].sig = 1;
		} else if (ae.encoding == AUDIO_ENCODING_ULINEAR_LE) {
			cap->enc[nenc].le = 1;
			cap->enc[nenc].sig = 0;
		} else if (ae.encoding == AUDIO_ENCODING_ULINEAR_BE) {
			cap->enc[nenc].le = 0;
			cap->enc[nenc].sig = 0;
		} else if (ae.encoding == AUDIO_ENCODING_SLINEAR) {
			cap->enc[nenc].le = SIO_LE_NATIVE;
			cap->enc[nenc].sig = 1;
		} else if (ae.encoding == AUDIO_ENCODING_ULINEAR) {
			cap->enc[nenc].le = SIO_LE_NATIVE;
			cap->enc[nenc].sig = 0;
		} else {
			/* unsipported encoding */
			continue;
		}
		cap->enc[nenc].bits = ae.precision;
		cap->enc[nenc].bps = ae.bps;
		cap->enc[nenc].msb = ae.msb;
		enc_map |= (1 << nenc);
		nenc++;
	}

	/*
	 * fill channels
	 *
	 * for now we're lucky: all kernel devices assume that the
	 * number of channels and the encoding are independent so we can
	 * use the current encoding and try various channels.
	 */
	if (hdl->sio.mode & SIO_PLAY) {
		memcpy(&cap->pchan, chans, NCHANS * sizeof(unsigned int));
		for (i = 0; i < NCHANS; i++) {
			if (sio_sun_tryinfo(hdl, NULL, chans[i], 0, 0))
				pchan_map |= (1 << i);
		}
	}
	if (hdl->sio.mode & SIO_REC) {
		memcpy(&cap->rchan, chans, NCHANS * sizeof(unsigned int));
		for (i = 0; i < NCHANS; i++) {
			if (sio_sun_tryinfo(hdl, NULL, 0, chans[i], 0))
				rchan_map |= (1 << i);
		}
	}

	/*
	 * fill rates
	 *
	 * rates are not independent from other parameters (eg. on
	 * uaudio devices), so certain rates may not be allowed with
	 * certain encodings. We have to check rates for all encodings
	 */
	memcpy(&cap->rate, rates, NRATES * sizeof(unsigned int));
	for (j = 0; j < nenc; j++) {
		rate_map = 0;
		for (i = 0; i < NRATES; i++) {
			if (sio_sun_tryinfo(hdl, &cap->enc[j], 0, 0, rates[i]))
				rate_map |= (1 << i);
		}
		for (conf = 0; conf < nconf; conf++) {
			if (cap->confs[conf].rate == rate_map) {
				cap->confs[conf].enc |= (1 << j);
				break;
			}
		}
		if (conf == nconf) {
			if (nconf == SIO_NCONF)
				break;
			cap->confs[nconf].enc = (1 << j);
			cap->confs[nconf].pchan = pchan_map;
			cap->confs[nconf].rchan = rchan_map;
			cap->confs[nconf].rate = rate_map;
			nconf++;
		}
	}
	cap->nconf = nconf;
	if (!sio_sun_setpar(&hdl->sio, &savepar))
		return 0;
	return 1;
#undef NCHANS
#undef NRATES
}

struct sio_hdl *
_sio_sun_open(const char *str, unsigned int mode, int nbio)
{
	int fd, flags, fullduplex;
	struct audio_info aui;
	struct sio_sun_hdl *hdl;
	struct sio_par par;
	char path[PATH_MAX];

	switch (*str) {
	case '/':
		str++;
		break;
	default:
		DPRINTF("_sio_sun_open: %s: '/<devnum>' expected\n", str);
		return NULL;
	}
	hdl = malloc(sizeof(struct sio_sun_hdl));
	if (hdl == NULL)
		return NULL;
	_sio_create(&hdl->sio, &sio_sun_ops, mode, nbio);

	snprintf(path, sizeof(path), DEVPATH_PREFIX "%s", str);
	if (mode == (SIO_PLAY | SIO_REC))
		flags = O_RDWR;
	else
		flags = (mode & SIO_PLAY) ? O_WRONLY : O_RDONLY;

	while ((fd = open(path, flags | O_NONBLOCK | O_CLOEXEC)) < 0) {
		if (errno == EINTR)
			continue;
		DPERROR(path);
		goto bad_free;
	}

	/*
	 * pause the device
	 */
	AUDIO_INITINFO(&aui);
	if (mode & SIO_PLAY)
		aui.play.pause = 1;
	if (mode & SIO_REC)
		aui.record.pause = 1;
	if (ioctl(fd, AUDIO_SETINFO, &aui) < 0) {
		DPERROR("sio_open_sun: setinfo");
		goto bad_close;
	}
	/*
	 * If both play and record are requested then
	 * set full duplex mode.
	 */
	if (mode == (SIO_PLAY | SIO_REC)) {
		fullduplex = 1;
		if (ioctl(fd, AUDIO_SETFD, &fullduplex) < 0) {
			DPRINTF("sio_open_sun: %s: can't set full-duplex\n", path);
			goto bad_close;
		}
	}
	hdl->fd = fd;

	/*
	 * Default parameters may not be compatible with libsndio (eg. mulaw
	 * encodings, different playback and recording parameters, etc...), so
	 * set parameters to a random value. If the requested parameters are
	 * not supported by the device, then sio_setpar() will pick supported
	 * ones.
	 */
	sio_initpar(&par);
	par.rate = 48000;
	par.le = SIO_LE_NATIVE;
	par.sig = 1;
	par.bits = 16;
	par.appbufsz = 1200;
	if (!sio_setpar(&hdl->sio, &par))
		goto bad_close;
	return (struct sio_hdl *)hdl;
 bad_close:
	while (close(fd) < 0 && errno == EINTR)
		; /* retry */
 bad_free:
	free(hdl);
	return NULL;
}

static void
sio_sun_close(struct sio_hdl *sh)
{
	struct sio_sun_hdl *hdl = (struct sio_sun_hdl *)sh;

	while (close(hdl->fd) < 0 && errno == EINTR)
		; /* retry */
	free(hdl);
}

static int
sio_sun_start(struct sio_hdl *sh)
{
	struct sio_sun_hdl *hdl = (struct sio_sun_hdl *)sh;
	struct audio_info aui;

	hdl->obpf = hdl->sio.par.pchan * hdl->sio.par.bps;
	hdl->ibpf = hdl->sio.par.rchan * hdl->sio.par.bps;
	hdl->ibytes = 0;
	hdl->obytes = 0;
	hdl->ierr = 0;
	hdl->oerr = 0;
	hdl->idelta = 0;
	hdl->odelta = 0;

	if (hdl->sio.mode & SIO_PLAY) {
		/*
		 * keep the device paused and let sio_sun_write() trigger the
		 * start later, to avoid buffer underruns
		 */
		hdl->filling = 1;
	} else {
		/*
		 * no play buffers to fill, start now!
		 */
		AUDIO_INITINFO(&aui);
		if (hdl->sio.mode & SIO_REC)
			aui.record.pause = 0;
		if (ioctl(hdl->fd, AUDIO_SETINFO, &aui) < 0) {
			DPERROR("sio_sun_start: setinfo");
			hdl->sio.eof = 1;
			return 0;
		}
		hdl->filling = 0;
		_sio_onmove_cb(&hdl->sio, 0);
	}
	return 1;
}

static int
sio_sun_stop(struct sio_hdl *sh)
{
	struct sio_sun_hdl *hdl = (struct sio_sun_hdl *)sh;
	struct audio_info aui;
	int mode;

	if (ioctl(hdl->fd, AUDIO_GETINFO, &aui) < 0) {
		DPERROR("sio_sun_stop: getinfo");
		hdl->sio.eof = 1;
		return 0;
	}
	mode = aui.mode;

	/*
	 * there's no way to drain the device without blocking, so just
	 * stop it until the kernel driver get fixed
	 */
	AUDIO_INITINFO(&aui);
	aui.mode = 0;
	if (hdl->sio.mode & SIO_PLAY)
		aui.play.pause = 1;
	if (hdl->sio.mode & SIO_REC)
		aui.record.pause = 1;
	if (ioctl(hdl->fd, AUDIO_SETINFO, &aui) < 0) {
		DPERROR("sio_sun_stop: setinfo1");
		hdl->sio.eof = 1;
		return 0;
	}
	AUDIO_INITINFO(&aui);
	aui.mode = mode;
	if (ioctl(hdl->fd, AUDIO_SETINFO, &aui) < 0) {
		DPERROR("sio_sun_stop: setinfo2");
		hdl->sio.eof = 1;
		return 0;
	}
	return 1;
}

static int
sio_sun_setpar(struct sio_hdl *sh, struct sio_par *par)
{
#define NRETRIES 8
	struct sio_sun_hdl *hdl = (struct sio_sun_hdl *)sh;
	struct audio_info aui;
	unsigned int i, infr, ibpf, onfr, obpf;
	unsigned int bufsz, round;
	unsigned int rate, req_rate, prec, enc;

	/*
	 * try to set parameters until the device accepts
	 * a common encoding and rate for play and record
	 */
	rate = par->rate;
	prec = par->bits;
	sio_sun_enctoinfo(hdl, &enc, par);
	for (i = 0;; i++) {
		if (i == NRETRIES) {
			DPRINTF("sio_sun_setpar: couldn't set parameters\n");
			hdl->sio.eof = 1;
			return 0;
		}
		AUDIO_INITINFO(&aui);
		if (hdl->sio.mode & SIO_PLAY) {
			aui.play.sample_rate = rate;
			aui.play.precision = prec;
			aui.play.encoding = enc;
			aui.play.channels = par->pchan;
		}
		if (hdl->sio.mode & SIO_REC) {
			aui.record.sample_rate = rate;
			aui.record.precision = prec;
			aui.record.encoding = enc;
			aui.record.channels = par->rchan;
		}
		DPRINTFN(2, "sio_sun_setpar: %i: trying pars = %u/%u/%u\n",
		    i, rate, prec, enc);
		if (ioctl(hdl->fd, AUDIO_SETINFO, &aui) < 0 && errno != EINVAL) {
			DPERROR("sio_sun_setpar: setinfo(pars)");
			hdl->sio.eof = 1;
			return 0;
		}
		if (ioctl(hdl->fd, AUDIO_GETINFO, &aui) < 0) {
			DPERROR("sio_sun_setpar: getinfo(pars)");
			hdl->sio.eof = 1;
			return 0;
		}
		enc = (hdl->sio.mode & SIO_REC) ?
		    aui.record.encoding : aui.play.encoding;
		switch (enc) {
		case AUDIO_ENCODING_SLINEAR_LE:
		case AUDIO_ENCODING_SLINEAR_BE:
		case AUDIO_ENCODING_ULINEAR_LE:
		case AUDIO_ENCODING_ULINEAR_BE:
		case AUDIO_ENCODING_SLINEAR:
		case AUDIO_ENCODING_ULINEAR:
			break;
		default:
			DPRINTF("sio_sun_setpar: couldn't set linear encoding\n");
			hdl->sio.eof = 1;
			return 0;
		}
		if (hdl->sio.mode != (SIO_REC | SIO_PLAY))
			break;
		if (aui.play.sample_rate == aui.record.sample_rate &&
		    aui.play.precision == aui.record.precision &&
		    aui.play.encoding == aui.record.encoding)
			break;
		if (i < NRETRIES / 2) {
			rate = aui.play.sample_rate;
			prec = aui.play.precision;
			enc = aui.play.encoding;
		} else {
			rate = aui.record.sample_rate;
			prec = aui.record.precision;
			enc = aui.record.encoding;
		}
	}

	/*
	 * If the rate that the hardware is using is different than
	 * the requested rate, scale buffer sizes so they will be the
	 * same time duration as what was requested.  This just gets
	 * the rates to use for scaling, that actual scaling is done
	 * later.
	 */
	rate = (hdl->sio.mode & SIO_REC) ? aui.record.sample_rate :
	    aui.play.sample_rate;
	req_rate = rate;
	if (par->rate && par->rate != ~0U)
		req_rate = par->rate;

	/*
	 * if block size and buffer size are not both set then
	 * set the blocksize to half the buffer size
	 */
	bufsz = par->appbufsz;
	round = par->round;
	if (bufsz != ~0U) {
		bufsz = bufsz * rate / req_rate;
		if (round == ~0U)
			round = (bufsz + 1) / 2;
		else
			round = round * rate / req_rate;
	} else if (round != ~0U) {
		round = round * rate / req_rate;
		bufsz = round * 2;
	} else
		return 1;

	/*
	 * get the play/record frame size in bytes
	 */
	if (ioctl(hdl->fd, AUDIO_GETINFO, &aui) < 0) {
		DPERROR("sio_sun_setpar: GETINFO");
		hdl->sio.eof = 1;
		return 0;
	}
	ibpf = (hdl->sio.mode & SIO_REC) ?
	    aui.record.channels * aui.record.bps : 1;
	obpf = (hdl->sio.mode & SIO_PLAY) ?
	    aui.play.channels * aui.play.bps : 1;

	DPRINTFN(2, "sio_sun_setpar: bpf = (%u, %u)\n", ibpf, obpf);

	/*
	 * try to set parameters until the device accepts
	 * a common block size for play and record
	 */
	for (i = 0; i < NRETRIES; i++) {
		AUDIO_INITINFO(&aui);
		aui.hiwat = (bufsz + round - 1) / round;
		aui.lowat = aui.hiwat;
		if (hdl->sio.mode & SIO_REC)
			aui.record.block_size = round * ibpf;
		if (hdl->sio.mode & SIO_PLAY)
			aui.play.block_size = round * obpf;
		if (ioctl(hdl->fd, AUDIO_SETINFO, &aui) < 0) {
			DPERROR("sio_sun_setpar2: SETINFO");
			hdl->sio.eof = 1;
			return 0;
		}
		if (ioctl(hdl->fd, AUDIO_GETINFO, &aui) < 0) {
			DPERROR("sio_sun_setpar2: GETINFO");
			hdl->sio.eof = 1;
			return 0;
		}
		infr = aui.record.block_size / ibpf;
		onfr = aui.play.block_size / obpf;
		DPRINTFN(2, "sio_sun_setpar: %i: trying round = %u -> (%u, %u)\n",
		    i, round, infr, onfr);

		/*
		 * if half-duplex or both block sizes match, we're done
		 */
		if (hdl->sio.mode != (SIO_REC | SIO_PLAY) || infr == onfr) {
			DPRINTFN(2, "sio_sun_setpar: blocksize ok\n");
			return 1;
		}

		/*
		 * half of the retries, retry with the smaller value,
		 * then with the larger returned value
		 */
		if (i < NRETRIES / 2)
			round = infr < onfr ? infr : onfr;
		else
			round = infr < onfr ? onfr : infr;
	}
	DPRINTFN(2, "sio_sun_setpar: couldn't find a working blocksize\n");
	hdl->sio.eof = 1;
	return 0;
#undef NRETRIES
}

static int
sio_sun_getpar(struct sio_hdl *sh, struct sio_par *par)
{
	struct sio_sun_hdl *hdl = (struct sio_sun_hdl *)sh;
	struct audio_info aui;

	if (ioctl(hdl->fd, AUDIO_GETINFO, &aui) < 0) {
		DPERROR("sio_sun_getpar: getinfo");
		hdl->sio.eof = 1;
		return 0;
	}
	if (hdl->sio.mode & SIO_PLAY) {
		par->rate = aui.play.sample_rate;
		if (!sio_sun_infotoenc(hdl, &aui.play, par))
			return 0;
	} else if (hdl->sio.mode & SIO_REC) {
		par->rate = aui.record.sample_rate;
		if (!sio_sun_infotoenc(hdl, &aui.record, par))
			return 0;
	} else
		return 0;
	par->pchan = (hdl->sio.mode & SIO_PLAY) ?
	    aui.play.channels : 0;
	par->rchan = (hdl->sio.mode & SIO_REC) ?
	    aui.record.channels : 0;
	par->round = (hdl->sio.mode & SIO_REC) ?
	    aui.record.block_size / (par->bps * par->rchan) :
	    aui.play.block_size / (par->bps * par->pchan);
	par->appbufsz = aui.hiwat * par->round;
	par->bufsz = par->appbufsz;
	par->xrun = SIO_IGNORE;
	return 1;
}

static size_t
sio_sun_read(struct sio_hdl *sh, void *buf, size_t len)
{
	struct sio_sun_hdl *hdl = (struct sio_sun_hdl *)sh;
	ssize_t n;

	while ((n = read(hdl->fd, buf, len)) < 0) {
		if (errno == EINTR)
			continue;
		if (errno != EAGAIN) {
			DPERROR("sio_sun_read: read");
			hdl->sio.eof = 1;
		}
		return 0;
	}
	if (n == 0) {
		DPRINTF("sio_sun_read: eof\n");
		hdl->sio.eof = 1;
		return 0;
	}
	return n;
}

static size_t
sio_sun_autostart(struct sio_sun_hdl *hdl)
{
	struct audio_info aui;
	struct pollfd pfd;

	pfd.fd = hdl->fd;
	pfd.events = POLLOUT;
	while (poll(&pfd, 1, 0) < 0) {
		if (errno == EINTR)
			continue;
		DPERROR("sio_sun_autostart: poll");
		hdl->sio.eof = 1;
		return 0;
	}
	if (!(pfd.revents & POLLOUT)) {
		hdl->filling = 0;
		AUDIO_INITINFO(&aui);
		if (hdl->sio.mode & SIO_PLAY)
			aui.play.pause = 0;
		if (hdl->sio.mode & SIO_REC)
			aui.record.pause = 0;
		if (ioctl(hdl->fd, AUDIO_SETINFO, &aui) < 0) {
			DPERROR("sio_sun_autostart: setinfo");
			hdl->sio.eof = 1;
			return 0;
		}
		_sio_onmove_cb(&hdl->sio, 0);
	}
	return 1;
}

static size_t
sio_sun_write(struct sio_hdl *sh, const void *buf, size_t len)
{
	struct sio_sun_hdl *hdl = (struct sio_sun_hdl *)sh;
	const unsigned char *data = buf;
	ssize_t n, todo;

	todo = len;
	while ((n = write(hdl->fd, data, todo)) < 0) {
		if (errno == EINTR)
			continue;
		if (errno != EAGAIN) {
			DPERROR("sio_sun_write: write");
			hdl->sio.eof = 1;
		}
 		return 0;
	}
	if (hdl->filling) {
		if (!sio_sun_autostart(hdl))
			return 0;
	}
	return n;
}

static int
sio_sun_nfds(struct sio_hdl *hdl)
{
	return 1;
}

static int
sio_sun_pollfd(struct sio_hdl *sh, struct pollfd *pfd, int events)
{
	struct sio_sun_hdl *hdl = (struct sio_sun_hdl *)sh;

	pfd->fd = hdl->fd;
	pfd->events = events;
	return 1;
}

int
sio_sun_revents(struct sio_hdl *sh, struct pollfd *pfd)
{
	struct sio_sun_hdl *hdl = (struct sio_sun_hdl *)sh;
	struct audio_pos ap;
	int dierr = 0, doerr = 0, offset, delta;
	int revents = pfd->revents;

	if (!hdl->sio.started)
		return pfd->revents;
	if (ioctl(hdl->fd, AUDIO_GETPOS, &ap) < 0) {
		DPERROR("sio_sun_revents: GETPOS");
		hdl->sio.eof = 1;
		return POLLHUP;
	}
	if (hdl->sio.mode & SIO_PLAY) {
		delta = (ap.play_pos - hdl->obytes) / hdl->obpf;
		doerr = (ap.play_xrun - hdl->oerr) / hdl->obpf;
		hdl->obytes = ap.play_pos;
		hdl->oerr = ap.play_xrun;
		hdl->odelta += delta;	
		if (!(hdl->sio.mode & SIO_REC)) {
			hdl->idelta += delta;
			dierr = doerr;
		}
		if (doerr > 0)
			DPRINTFN(2, "play xrun %d\n", doerr);
	}
	if (hdl->sio.mode & SIO_REC) {
		delta = (ap.rec_pos - hdl->ibytes) / hdl->ibpf;
		dierr = (ap.rec_xrun - hdl->ierr) / hdl->ibpf;
		hdl->ibytes = ap.rec_pos;
		hdl->ierr = ap.rec_xrun;
		hdl->idelta += delta;
		if (!(hdl->sio.mode & SIO_PLAY)) {
			hdl->odelta += delta;
			doerr = dierr;
		}
		if (dierr > 0)
			DPRINTFN(2, "rec xrun %d\n", dierr);
	}

	/*
	 * GETPOS reports positions including xruns,
	 * so we have to substract to get the real position
	 */
	hdl->idelta -= dierr;
	hdl->odelta -= doerr;

	offset = doerr - dierr;
	if (offset > 0) {
		hdl->sio.rdrop += offset * hdl->ibpf;
		hdl->idelta -= offset;
		DPRINTFN(2, "will drop %d and pause %d\n", offset, doerr);
	} else if (offset < 0) {
		hdl->sio.wsil += -offset * hdl->obpf;
		hdl->odelta -= -offset;
		DPRINTFN(2, "will insert %d and pause %d\n", -offset, dierr);
	}

	delta = (hdl->idelta > hdl->odelta) ? hdl->idelta : hdl->odelta;
	if (delta > 0) {
		_sio_onmove_cb(&hdl->sio, delta);
		hdl->idelta -= delta;
		hdl->odelta -= delta;
	}

	if (hdl->filling)
		revents |= POLLOUT; /* XXX: is this necessary ? */
	return revents;
}