drivers/staging/easycap/easycap_sound.c

/******************************************************************************
*                                                                             *
*  easycap_sound.c                                                            *
*                                                                             *
*  Audio driver for EasyCAP USB2.0 Video Capture Device DC60                  *
*                                                                             *
*                                                                             *
******************************************************************************/
/*
 *
 *  Copyright (C) 2010 R.M. Thomas  <rmthomas@sciolus.org>
 *
 *
 *  This is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  The software is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this software; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
*/
/*****************************************************************************/

#include "easycap.h"

/*--------------------------------------------------------------------------*/
/*
 *  PARAMETERS USED WHEN REGISTERING THE AUDIO INTERFACE
 */
/*--------------------------------------------------------------------------*/
static const struct snd_pcm_hardware alsa_hardware = {
	.info = SNDRV_PCM_INFO_BLOCK_TRANSFER |
		SNDRV_PCM_INFO_MMAP           |
		SNDRV_PCM_INFO_INTERLEAVED    |
		SNDRV_PCM_INFO_MMAP_VALID,
	.formats = SNDRV_PCM_FMTBIT_S16_LE,
	.rates = SNDRV_PCM_RATE_32000 | SNDRV_PCM_RATE_48000,
	.rate_min = 32000,
	.rate_max = 48000,
	.channels_min = 2,
	.channels_max = 2,
	.buffer_bytes_max = PAGE_SIZE *
			    PAGES_PER_AUDIO_FRAGMENT *
			    AUDIO_FRAGMENT_MANY,
	.period_bytes_min = PAGE_SIZE * PAGES_PER_AUDIO_FRAGMENT,
	.period_bytes_max = PAGE_SIZE * PAGES_PER_AUDIO_FRAGMENT * 2,
	.periods_min = AUDIO_FRAGMENT_MANY,
	.periods_max = AUDIO_FRAGMENT_MANY * 2,
};


/*****************************************************************************/
/*---------------------------------------------------------------------------*/
/*
 *  ON COMPLETION OF AN AUDIO URB ITS DATA IS COPIED TO THE DAM BUFFER
 *  PROVIDED peasycap->audio_idle IS ZERO.  REGARDLESS OF THIS BEING TRUE,
 *  IT IS RESUBMITTED PROVIDED peasycap->audio_isoc_streaming IS NOT ZERO.
 */
/*---------------------------------------------------------------------------*/
void
easycap_alsa_complete(struct urb *purb)
{
	struct easycap *peasycap;
	struct snd_pcm_substream *pss;
	struct snd_pcm_runtime *prt;
	int dma_bytes, fragment_bytes;
	int isfragment;
	u8 *p1, *p2;
	s16 tmp;
	int i, j, more, much, rc;
#ifdef UPSAMPLE
	int k;
	s16 oldaudio, newaudio, delta;
#endif /*UPSAMPLE*/

	JOT(16, "\n");

	if (!purb) {
		SAY("ERROR: purb is NULL\n");
		return;
	}
	peasycap = purb->context;
	if (!peasycap) {
		SAY("ERROR: peasycap is NULL\n");
		return;
	}
	much = 0;
	if (peasycap->audio_idle) {
		JOM(16, "%i=audio_idle  %i=audio_isoc_streaming\n",
		    peasycap->audio_idle, peasycap->audio_isoc_streaming);
		if (peasycap->audio_isoc_streaming)
			goto resubmit;
	}
/*---------------------------------------------------------------------------*/
	pss = peasycap->psubstream;
	if (!pss)
		goto resubmit;
	prt = pss->runtime;
	if (!prt)
		goto resubmit;
	dma_bytes = (int)prt->dma_bytes;
	if (0 == dma_bytes)
		goto resubmit;
	fragment_bytes = 4 * ((int)prt->period_size);
	if (0 == fragment_bytes)
		goto resubmit;
/* -------------------------------------------------------------------------*/
	if (purb->status) {
		if ((-ESHUTDOWN == purb->status) || (-ENOENT == purb->status)) {
			JOM(16, "urb status -ESHUTDOWN or -ENOENT\n");
			return;
		}
		SAM("ERROR: non-zero urb status: -%s: %d\n",
		    strerror(purb->status), purb->status);
		goto resubmit;
	}
/*---------------------------------------------------------------------------*/
/*
 *  PROCEED HERE WHEN NO ERROR
 */
/*---------------------------------------------------------------------------*/

#ifdef UPSAMPLE
	oldaudio = peasycap->oldaudio;
#endif /*UPSAMPLE*/

	for (i = 0;  i < purb->number_of_packets; i++) {
		if (purb->iso_frame_desc[i].status < 0) {
			SAM("-%s: %d\n",
			    strerror(purb->iso_frame_desc[i].status),
			    purb->iso_frame_desc[i].status);
		}
		if (purb->iso_frame_desc[i].status) {
			JOM(12, "discarding audio samples because "
			    "%i=purb->iso_frame_desc[i].status\n",
			    purb->iso_frame_desc[i].status);
			continue;
		}
		more = purb->iso_frame_desc[i].actual_length;
		if (more == 0) {
			peasycap->audio_mt++;
			continue;
		}
		if (0 > more) {
			SAM("MISTAKE: more is negative\n");
			return;
		}

		if (peasycap->audio_mt) {
			JOM(12, "%4i empty audio urb frames\n",
			    peasycap->audio_mt);
			peasycap->audio_mt = 0;
		}

		p1 = (u8 *)(purb->transfer_buffer +
				purb->iso_frame_desc[i].offset);

		/*
		 *  COPY more BYTES FROM ISOC BUFFER
		 *  TO THE DMA BUFFER, CONVERTING
		 *  8-BIT MONO TO 16-BIT SIGNED
		 *  LITTLE-ENDIAN SAMPLES IF NECESSARY
		 */
		while (more) {
			much = dma_bytes - peasycap->dma_fill;
			if (0 > much) {
				SAM("MISTAKE: much is negative\n");
				return;
			}
			if (0 == much) {
				peasycap->dma_fill = 0;
				peasycap->dma_next = fragment_bytes;
				JOM(8, "wrapped dma buffer\n");
			}
			if (!peasycap->microphone) {
				if (much > more)
					much = more;
				memcpy(prt->dma_area + peasycap->dma_fill,
					p1, much);
				p1 += much;
				more -= much;
			} else {
#ifdef UPSAMPLE
				if (much % 16)
					JOM(8, "MISTAKE? much"
					    " is not divisible by 16\n");
				if (much > (16 * more))
					much = 16 * more;
				p2 = (u8 *)(prt->dma_area + peasycap->dma_fill);

				for (j = 0;  j < (much / 16);  j++) {
					newaudio =  ((int) *p1) - 128;
					newaudio = 128 * newaudio;

					delta = (newaudio - oldaudio) / 4;
					tmp = oldaudio + delta;

					for (k = 0;  k < 4;  k++) {
						*p2 = (0x00FF & tmp);
						*(p2 + 1) = (0xFF00 & tmp) >> 8;
						p2 += 2;
						*p2 = (0x00FF & tmp);
						*(p2 + 1) = (0xFF00 & tmp) >> 8;
						p2 += 2;
						tmp += delta;
					}
					p1++;
					more--;
					oldaudio = tmp;
				}
#else /*!UPSAMPLE*/
				if (much > (2 * more))
					much = 2 * more;
				p2 = (u8 *)(prt->dma_area + peasycap->dma_fill);

				for (j = 0;  j < (much / 2);  j++) {
					tmp = ((int) *p1) - 128;
					tmp = 128 * tmp;
					*p2 = (0x00FF & tmp);
					*(p2 + 1) = (0xFF00 & tmp) >> 8;
					p1++;
					p2 += 2;
					more--;
				}
#endif /*UPSAMPLE*/
			}
			peasycap->dma_fill += much;
			if (peasycap->dma_fill >= peasycap->dma_next) {
				isfragment = peasycap->dma_fill / fragment_bytes;
				if (0 > isfragment) {
					SAM("MISTAKE: isfragment is negative\n");
					return;
				}
				peasycap->dma_read = (isfragment - 1) * fragment_bytes;
				peasycap->dma_next = (isfragment + 1) * fragment_bytes;
				if (dma_bytes < peasycap->dma_next)
					peasycap->dma_next = fragment_bytes;

				if (0 <= peasycap->dma_read) {
					JOM(8, "snd_pcm_period_elapsed(), %i="
					    "isfragment\n", isfragment);
					snd_pcm_period_elapsed(pss);
				}
			}
		}

#ifdef UPSAMPLE
		peasycap->oldaudio = oldaudio;
#endif /*UPSAMPLE*/

	}
/*---------------------------------------------------------------------------*/
/*
 *  RESUBMIT THIS URB
 */
/*---------------------------------------------------------------------------*/
resubmit:
	if (peasycap->audio_isoc_streaming == 0)
		return;

	rc = usb_submit_urb(purb, GFP_ATOMIC);
	if (rc) {
		if ((-ENODEV != rc) && (-ENOENT != rc)) {
			SAM("ERROR: while %i=audio_idle, usb_submit_urb failed "
			    "with rc: -%s :%d\n",
				peasycap->audio_idle, strerror(rc), rc);
		}
		if (0 < peasycap->audio_isoc_streaming)
			peasycap->audio_isoc_streaming--;
	}
	return;
}
/*****************************************************************************/
static int easycap_alsa_open(struct snd_pcm_substream *pss)
{
	struct snd_pcm *psnd_pcm;
	struct snd_card *psnd_card;
	struct easycap *peasycap;

	JOT(4, "\n");
	if (!pss) {
		SAY("ERROR:  pss is NULL\n");
		return -EFAULT;
	}
	psnd_pcm = pss->pcm;
	if (!psnd_pcm) {
		SAY("ERROR:  psnd_pcm is NULL\n");
		return -EFAULT;
	}
	psnd_card = psnd_pcm->card;
	if (!psnd_card) {
		SAY("ERROR:  psnd_card is NULL\n");
		return -EFAULT;
	}

	peasycap = psnd_card->private_data;
	if (!peasycap) {
		SAY("ERROR:  peasycap is NULL\n");
		return -EFAULT;
	}
	if (peasycap->psnd_card != psnd_card) {
		SAM("ERROR: bad peasycap->psnd_card\n");
		return -EFAULT;
	}
	if (peasycap->psubstream) {
		SAM("ERROR: bad peasycap->psubstream\n");
		return -EFAULT;
	}
	pss->private_data = peasycap;
	peasycap->psubstream = pss;
	pss->runtime->hw = peasycap->alsa_hardware;
	pss->runtime->private_data = peasycap;
	pss->private_data = peasycap;

	if (0 != easycap_sound_setup(peasycap)) {
		JOM(4, "ending unsuccessfully\n");
		return -EFAULT;
	}
	JOM(4, "ending successfully\n");
	return 0;
}
/*****************************************************************************/
static int easycap_alsa_close(struct snd_pcm_substream *pss)
{
	struct easycap *peasycap;

	JOT(4, "\n");
	if (!pss) {
		SAY("ERROR:  pss is NULL\n");
		return -EFAULT;
	}
	peasycap = snd_pcm_substream_chip(pss);
	if (!peasycap) {
		SAY("ERROR:  peasycap is NULL\n");
		return -EFAULT;
	}
	pss->private_data = NULL;
	peasycap->psubstream = NULL;
	JOT(4, "ending successfully\n");
	return 0;
}
/*****************************************************************************/
static int easycap_alsa_vmalloc(struct snd_pcm_substream *pss, size_t sz)
{
	struct snd_pcm_runtime *prt;
	JOT(4, "\n");

	if (!pss) {
		SAY("ERROR:  pss is NULL\n");
		return -EFAULT;
	}
	prt = pss->runtime;
	if (!prt) {
		SAY("ERROR: substream.runtime is NULL\n");
		return -EFAULT;
	}
	if (prt->dma_area) {
		if (prt->dma_bytes > sz)
			return 0;
		vfree(prt->dma_area);
	}
	prt->dma_area = vmalloc(sz);
	if (!prt->dma_area)
		return -ENOMEM;
	prt->dma_bytes = sz;
	return 0;
}
/*****************************************************************************/
static int easycap_alsa_hw_params(struct snd_pcm_substream *pss,
				 struct snd_pcm_hw_params *phw)
{
	int rc;

	JOT(4, "%i\n", (params_buffer_bytes(phw)));
	if (!pss) {
		SAY("ERROR:  pss is NULL\n");
		return -EFAULT;
	}
	rc = easycap_alsa_vmalloc(pss, params_buffer_bytes(phw));
	if (rc)
		return rc;
	return 0;
}
/*****************************************************************************/
static int easycap_alsa_hw_free(struct snd_pcm_substream *pss)
{
	struct snd_pcm_runtime *prt;
	JOT(4, "\n");

	if (!pss) {
		SAY("ERROR:  pss is NULL\n");
		return -EFAULT;
	}
	prt = pss->runtime;
	if (!prt) {
		SAY("ERROR: substream.runtime is NULL\n");
		return -EFAULT;
	}
	if (prt->dma_area) {
		JOT(8, "prt->dma_area = %p\n", prt->dma_area);
		vfree(prt->dma_area);
		prt->dma_area = NULL;
	} else
		JOT(8, "dma_area already freed\n");
	return 0;
}
/*****************************************************************************/
static int easycap_alsa_prepare(struct snd_pcm_substream *pss)
{
	struct easycap *peasycap;
	struct snd_pcm_runtime *prt;

	JOT(4, "\n");
	if (!pss) {
		SAY("ERROR:  pss is NULL\n");
		return -EFAULT;
	}
	prt = pss->runtime;
	peasycap = snd_pcm_substream_chip(pss);
	if (!peasycap) {
		SAY("ERROR:  peasycap is NULL\n");
		return -EFAULT;
	}

	JOM(16, "ALSA decides %8i Hz=rate\n", pss->runtime->rate);
	JOM(16, "ALSA decides %8ld =period_size\n", pss->runtime->period_size);
	JOM(16, "ALSA decides %8i =periods\n", pss->runtime->periods);
	JOM(16, "ALSA decides %8ld =buffer_size\n", pss->runtime->buffer_size);
	JOM(16, "ALSA decides %8zd =dma_bytes\n", pss->runtime->dma_bytes);
	JOM(16, "ALSA decides %8ld =boundary\n", pss->runtime->boundary);
	JOM(16, "ALSA decides %8i =period_step\n", pss->runtime->period_step);
	JOM(16, "ALSA decides %8i =sample_bits\n", pss->runtime->sample_bits);
	JOM(16, "ALSA decides %8i =frame_bits\n", pss->runtime->frame_bits);
	JOM(16, "ALSA decides %8ld =min_align\n", pss->runtime->min_align);
	JOM(12, "ALSA decides %8ld =hw_ptr_base\n", pss->runtime->hw_ptr_base);
	JOM(12, "ALSA decides %8ld =hw_ptr_interrupt\n",
		pss->runtime->hw_ptr_interrupt);

	if (prt->dma_bytes != 4 * ((int)prt->period_size) * ((int)prt->periods)) {
		SAY("MISTAKE:  unexpected ALSA parameters\n");
		return -ENOENT;
	}
	return 0;
}
/*****************************************************************************/
static int easycap_alsa_ack(struct snd_pcm_substream *pss)
{
	return 0;
}
/*****************************************************************************/
static int easycap_alsa_trigger(struct snd_pcm_substream *pss, int cmd)
{
	struct easycap *peasycap;
	int retval;

	JOT(4, "%i=cmd cf %i=START %i=STOP\n", cmd, SNDRV_PCM_TRIGGER_START,
	    SNDRV_PCM_TRIGGER_STOP);
	if (!pss) {
		SAY("ERROR:  pss is NULL\n");
		return -EFAULT;
	}
	peasycap = snd_pcm_substream_chip(pss);
	if (!peasycap) {
		SAY("ERROR:  peasycap is NULL\n");
		return -EFAULT;
	}
	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START: {
		peasycap->audio_idle = 0;
		break;
	}
	case SNDRV_PCM_TRIGGER_STOP: {
		peasycap->audio_idle = 1;
		break;
	}
	default:
		retval = -EINVAL;
	}
	return 0;
}
/*****************************************************************************/
static snd_pcm_uframes_t easycap_alsa_pointer(struct snd_pcm_substream *pss)
{
	struct easycap *peasycap;
	snd_pcm_uframes_t offset;

	JOT(16, "\n");
	if (!pss) {
		SAY("ERROR:  pss is NULL\n");
		return -EFAULT;
	}
	peasycap = snd_pcm_substream_chip(pss);
	if (!peasycap) {
		SAY("ERROR:  peasycap is NULL\n");
		return -EFAULT;
	}
	if ((0 != peasycap->audio_eof) || (0 != peasycap->audio_idle)) {
		JOM(8, "returning -EIO because  "
		    "%i=audio_idle  %i=audio_eof\n",
		    peasycap->audio_idle, peasycap->audio_eof);
		return -EIO;
	}
/*---------------------------------------------------------------------------*/
	if (0 > peasycap->dma_read) {
		JOM(8, "returning -EBUSY\n");
		return -EBUSY;
	}
	offset = ((snd_pcm_uframes_t)peasycap->dma_read)/4;
	JOM(8, "ALSA decides %8i   =hw_ptr_base\n", (int)pss->runtime->hw_ptr_base);
	JOM(8, "ALSA decides %8i   =hw_ptr_interrupt\n",
	    (int)pss->runtime->hw_ptr_interrupt);
	JOM(8, "%7i=offset %7i=dma_read %7i=dma_next\n",
	    (int)offset, peasycap->dma_read, peasycap->dma_next);
	return offset;
}
/*****************************************************************************/
static struct page *
easycap_alsa_page(struct snd_pcm_substream *pss, unsigned long offset)
{
	return vmalloc_to_page(pss->runtime->dma_area + offset);
}
/*****************************************************************************/

static struct snd_pcm_ops easycap_alsa_pcm_ops = {
	.open      = easycap_alsa_open,
	.close     = easycap_alsa_close,
	.ioctl     = snd_pcm_lib_ioctl,
	.hw_params = easycap_alsa_hw_params,
	.hw_free   = easycap_alsa_hw_free,
	.prepare   = easycap_alsa_prepare,
	.ack       = easycap_alsa_ack,
	.trigger   = easycap_alsa_trigger,
	.pointer   = easycap_alsa_pointer,
	.page      = easycap_alsa_page,
};

/*****************************************************************************/
/*---------------------------------------------------------------------------*/
/*
 *  THE FUNCTION snd_card_create() HAS  THIS_MODULE  AS AN ARGUMENT.  THIS
 *  MEANS MODULE easycap.  BEWARE.
*/
/*---------------------------------------------------------------------------*/
int easycap_alsa_probe(struct easycap *peasycap)
{
	int rc;
	struct snd_card *psnd_card;
	struct snd_pcm *psnd_pcm;

	if (!peasycap) {
		SAY("ERROR: peasycap is NULL\n");
		return -ENODEV;
	}
	if (0 > peasycap->minor) {
		SAY("ERROR: no minor\n");
		return -ENODEV;
	}

	peasycap->alsa_hardware = alsa_hardware;
	if (peasycap->microphone) {
		peasycap->alsa_hardware.rates = SNDRV_PCM_RATE_32000;
		peasycap->alsa_hardware.rate_min = 32000;
		peasycap->alsa_hardware.rate_max = 32000;
	} else {
		peasycap->alsa_hardware.rates = SNDRV_PCM_RATE_48000;
		peasycap->alsa_hardware.rate_min = 48000;
		peasycap->alsa_hardware.rate_max = 48000;
	}

	if (0 != snd_card_create(SNDRV_DEFAULT_IDX1, "easycap_alsa",
				THIS_MODULE, 0, &psnd_card)) {
		SAY("ERROR: Cannot do ALSA snd_card_create()\n");
		return -EFAULT;
	}

	sprintf(&psnd_card->id[0], "EasyALSA%i", peasycap->minor);
	strcpy(&psnd_card->driver[0], EASYCAP_DRIVER_DESCRIPTION);
	strcpy(&psnd_card->shortname[0], "easycap_alsa");
	sprintf(&psnd_card->longname[0], "%s", &psnd_card->shortname[0]);

	psnd_card->dev = &peasycap->pusb_device->dev;
	psnd_card->private_data = peasycap;
	peasycap->psnd_card = psnd_card;

	rc = snd_pcm_new(psnd_card, "easycap_pcm", 0, 0, 1, &psnd_pcm);
	if (rc) {
		SAM("ERROR: Cannot do ALSA snd_pcm_new()\n");
		snd_card_free(psnd_card);
		return -EFAULT;
	}

	snd_pcm_set_ops(psnd_pcm, SNDRV_PCM_STREAM_CAPTURE,
			&easycap_alsa_pcm_ops);
	psnd_pcm->info_flags = 0;
	strcpy(&psnd_pcm->name[0], &psnd_card->id[0]);
	psnd_pcm->private_data = peasycap;
	peasycap->psnd_pcm = psnd_pcm;
	peasycap->psubstream = NULL;

	rc = snd_card_register(psnd_card);
	if (rc) {
		SAM("ERROR: Cannot do ALSA snd_card_register()\n");
		snd_card_free(psnd_card);
		return -EFAULT;
	}

	SAM("registered %s\n", &psnd_card->id[0]);
	return 0;
}

/*****************************************************************************/
/*****************************************************************************/
/*****************************************************************************/
/*****************************************************************************/
/*****************************************************************************/
/*****************************************************************************/
/*---------------------------------------------------------------------------*/
/*
 *  COMMON AUDIO INITIALIZATION
 */
/*---------------------------------------------------------------------------*/
int
easycap_sound_setup(struct easycap *peasycap)
{
	int rc;

	JOM(4, "starting initialization\n");

	if (!peasycap) {
		SAY("ERROR:  peasycap is NULL.\n");
		return -EFAULT;
	}
	if (!peasycap->pusb_device) {
		SAM("ERROR: peasycap->pusb_device is NULL\n");
		return -ENODEV;
	}
	JOM(16, "0x%08lX=peasycap->pusb_device\n", (long int)peasycap->pusb_device);

	rc = audio_setup(peasycap);
	JOM(8, "audio_setup() returned %i\n", rc);

	if (!peasycap->pusb_device) {
		SAM("ERROR: peasycap->pusb_device has become NULL\n");
		return -ENODEV;
	}
/*---------------------------------------------------------------------------*/
	if (!peasycap->pusb_device) {
		SAM("ERROR: peasycap->pusb_device has become NULL\n");
		return -ENODEV;
	}
	rc = usb_set_interface(peasycap->pusb_device, peasycap->audio_interface,
			       peasycap->audio_altsetting_on);
	JOM(8, "usb_set_interface(.,%i,%i) returned %i\n", peasycap->audio_interface,
	    peasycap->audio_altsetting_on, rc);

	rc = wakeup_device(peasycap->pusb_device);
	JOM(8, "wakeup_device() returned %i\n", rc);

	peasycap->audio_eof = 0;
	peasycap->audio_idle = 0;

	peasycap->timeval1.tv_sec  = 0;
	peasycap->timeval1.tv_usec = 0;

	submit_audio_urbs(peasycap);

	JOM(4, "finished initialization\n");
	return 0;
}
/*****************************************************************************/
/*---------------------------------------------------------------------------*/
/*
 *  SUBMIT ALL AUDIO URBS.
 */
/*---------------------------------------------------------------------------*/
int
submit_audio_urbs(struct easycap *peasycap)
{
	struct data_urb *pdata_urb;
	struct urb *purb;
	struct list_head *plist_head;
	int j, isbad, nospc, m, rc;
	int isbuf;

	if (!peasycap) {
		SAY("ERROR: peasycap is NULL\n");
		return -EFAULT;
	}
	if (!peasycap->purb_audio_head) {
		SAM("ERROR: peasycap->urb_audio_head uninitialized\n");
		return -EFAULT;
	}
	if (!peasycap->pusb_device) {
		SAM("ERROR: peasycap->pusb_device is NULL\n");
		return -EFAULT;
	}

	if (peasycap->audio_isoc_streaming) {
		JOM(4, "already streaming audio urbs\n");
		return 0;
	}

	JOM(4, "initial submission of all audio urbs\n");
	rc = usb_set_interface(peasycap->pusb_device,
			       peasycap->audio_interface,
			       peasycap->audio_altsetting_on);
	JOM(8, "usb_set_interface(.,%i,%i) returned %i\n",
	    peasycap->audio_interface,
	    peasycap->audio_altsetting_on, rc);

	isbad = 0;
	nospc = 0;
	m = 0;
	list_for_each(plist_head, peasycap->purb_audio_head) {
		pdata_urb = list_entry(plist_head, struct data_urb, list_head);
		if (pdata_urb && pdata_urb->purb) {
			purb = pdata_urb->purb;
			isbuf = pdata_urb->isbuf;

			purb->interval = 1;
			purb->dev = peasycap->pusb_device;
			purb->pipe = usb_rcvisocpipe(peasycap->pusb_device,
					peasycap->audio_endpointnumber);
			purb->transfer_flags = URB_ISO_ASAP;
			purb->transfer_buffer = peasycap->audio_isoc_buffer[isbuf].pgo;
			purb->transfer_buffer_length = peasycap->audio_isoc_buffer_size;
			purb->complete = easycap_alsa_complete;
			purb->context = peasycap;
			purb->start_frame = 0;
			purb->number_of_packets = peasycap->audio_isoc_framesperdesc;
			for (j = 0;  j < peasycap->audio_isoc_framesperdesc; j++) {
				purb->iso_frame_desc[j].offset = j * peasycap->audio_isoc_maxframesize;
				purb->iso_frame_desc[j].length = peasycap->audio_isoc_maxframesize;
			}

			rc = usb_submit_urb(purb, GFP_KERNEL);
			if (rc) {
				isbad++;
				SAM("ERROR: usb_submit_urb() failed"
				    " for urb with rc: -%s: %d\n",
				    strerror(rc), rc);
			} else {
				m++;
			}
		} else {
			isbad++;
		}
	}
	if (nospc) {
		SAM("-ENOSPC=usb_submit_urb() for %i urbs\n", nospc);
		SAM(".....  possibly inadequate USB bandwidth\n");
		peasycap->audio_eof = 1;
	}
	if (isbad) {
		JOM(4, "attempting cleanup instead of submitting\n");
		list_for_each(plist_head, (peasycap->purb_audio_head)) {
			pdata_urb = list_entry(plist_head, struct data_urb, list_head);
			if (pdata_urb && pdata_urb->purb)
				usb_kill_urb(pdata_urb->purb);
		}
		peasycap->audio_isoc_streaming = 0;
	} else {
		peasycap->audio_isoc_streaming = m;
		JOM(4, "submitted %i audio urbs\n", m);
	}

	return 0;
}
/*****************************************************************************/
/*---------------------------------------------------------------------------*/
/*
 *  KILL ALL AUDIO URBS.
 */
/*---------------------------------------------------------------------------*/
int
kill_audio_urbs(struct easycap *peasycap)
{
	int m;
	struct list_head *plist_head;
	struct data_urb *pdata_urb;

	if (!peasycap) {
		SAY("ERROR: peasycap is NULL\n");
		return -EFAULT;
	}

	if (!peasycap->audio_isoc_streaming) {
		JOM(8, "%i=audio_isoc_streaming, no audio urbs killed\n",
		    peasycap->audio_isoc_streaming);
		return 0;
	}

	if (!peasycap->purb_audio_head) {
		SAM("ERROR: peasycap->purb_audio_head is NULL\n");
		return -EFAULT;
	}

	peasycap->audio_isoc_streaming = 0;
	JOM(4, "killing audio urbs\n");
	m = 0;
	list_for_each(plist_head, (peasycap->purb_audio_head)) {
		pdata_urb = list_entry(plist_head, struct data_urb, list_head);
		if (pdata_urb && pdata_urb->purb) {
			usb_kill_urb(pdata_urb->purb);
			m++;
		}
	}
	JOM(4, "%i audio urbs killed\n", m);

	return 0;
}
/*****************************************************************************/