Avoid beyond bounds copy while caching ACL

[zen-stable.git] / sound / usb / pcm.c

/*
 *   This program 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.
 *
 *   This program 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 program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/usb/audio.h>
#include <linux/usb/audio-v2.h>

#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>

#include "usbaudio.h"
#include "card.h"
#include "quirks.h"
#include "debug.h"
#include "endpoint.h"
#include "helper.h"
#include "pcm.h"
#include "clock.h"
#include "power.h"

/* return the estimated delay based on USB frame counters */
snd_pcm_uframes_t snd_usb_pcm_delay(struct snd_usb_substream *subs,
                                    unsigned int rate)
{
        int current_frame_number;
        int frame_diff;
        int est_delay;

        current_frame_number = usb_get_current_frame_number(subs->dev);
        /*
         * HCD implementations use different widths, use lower 8 bits.
         * The delay will be managed up to 256ms, which is more than
         * enough
         */
        frame_diff = (current_frame_number - subs->last_frame_number) & 0xff;

        /* Approximation based on number of samples per USB frame (ms),
           some truncation for 44.1 but the estimate is good enough */
        est_delay =  subs->last_delay - (frame_diff * rate / 1000);
        if (est_delay < 0)
                est_delay = 0;
        return est_delay;
}

/*
 * return the current pcm pointer.  just based on the hwptr_done value.
 */
static snd_pcm_uframes_t snd_usb_pcm_pointer(struct snd_pcm_substream *substream)
{
        struct snd_usb_substream *subs;
        unsigned int hwptr_done;

        subs = (struct snd_usb_substream *)substream->runtime->private_data;
        spin_lock(&subs->lock);
        hwptr_done = subs->hwptr_done;
        substream->runtime->delay = snd_usb_pcm_delay(subs,
                                                substream->runtime->rate);
        spin_unlock(&subs->lock);
        return hwptr_done / (substream->runtime->frame_bits >> 3);
}

/*
 * find a matching audio format
 */
static struct audioformat *find_format(struct snd_usb_substream *subs, unsigned int format,
                                       unsigned int rate, unsigned int channels)
{
        struct list_head *p;
        struct audioformat *found = NULL;
        int cur_attr = 0, attr;

        list_for_each(p, &subs->fmt_list) {
                struct audioformat *fp;
                fp = list_entry(p, struct audioformat, list);
                if (!(fp->formats & (1uLL << format)))
                        continue;
                if (fp->channels != channels)
                        continue;
                if (rate < fp->rate_min || rate > fp->rate_max)
                        continue;
                if (! (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)) {
                        unsigned int i;
                        for (i = 0; i < fp->nr_rates; i++)
                                if (fp->rate_table[i] == rate)
                                        break;
                        if (i >= fp->nr_rates)
                                continue;
                }
                attr = fp->ep_attr & USB_ENDPOINT_SYNCTYPE;
                if (! found) {
                        found = fp;
                        cur_attr = attr;
                        continue;
                }
                /* avoid async out and adaptive in if the other method
                 * supports the same format.
                 * this is a workaround for the case like
                 * M-audio audiophile USB.
                 */
                if (attr != cur_attr) {
                        if ((attr == USB_ENDPOINT_SYNC_ASYNC &&
                             subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
                            (attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
                             subs->direction == SNDRV_PCM_STREAM_CAPTURE))
                                continue;
                        if ((cur_attr == USB_ENDPOINT_SYNC_ASYNC &&
                             subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
                            (cur_attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
                             subs->direction == SNDRV_PCM_STREAM_CAPTURE)) {
                                found = fp;
                                cur_attr = attr;
                                continue;
                        }
                }
                /* find the format with the largest max. packet size */
                if (fp->maxpacksize > found->maxpacksize) {
                        found = fp;
                        cur_attr = attr;
                }
        }
        return found;
}

static int init_pitch_v1(struct snd_usb_audio *chip, int iface,
                         struct usb_host_interface *alts,
                         struct audioformat *fmt)
{
        struct usb_device *dev = chip->dev;
        unsigned int ep;
        unsigned char data[1];
        int err;

        ep = get_endpoint(alts, 0)->bEndpointAddress;

        data[0] = 1;
        if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
                                   USB_TYPE_CLASS|USB_RECIP_ENDPOINT|USB_DIR_OUT,
                                   UAC_EP_CS_ATTR_PITCH_CONTROL << 8, ep,
                                   data, sizeof(data))) < 0) {
                snd_printk(KERN_ERR "%d:%d:%d: cannot set enable PITCH\n",
                           dev->devnum, iface, ep);
                return err;
        }

        return 0;
}

static int init_pitch_v2(struct snd_usb_audio *chip, int iface,
                         struct usb_host_interface *alts,
                         struct audioformat *fmt)
{
        struct usb_device *dev = chip->dev;
        unsigned char data[1];
        unsigned int ep;
        int err;

        ep = get_endpoint(alts, 0)->bEndpointAddress;

        data[0] = 1;
        if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
                                   USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
                                   UAC2_EP_CS_PITCH << 8, 0,
                                   data, sizeof(data))) < 0) {
                snd_printk(KERN_ERR "%d:%d:%d: cannot set enable PITCH (v2)\n",
                           dev->devnum, iface, fmt->altsetting);
                return err;
        }

        return 0;
}

/*
 * initialize the pitch control and sample rate
 */
int snd_usb_init_pitch(struct snd_usb_audio *chip, int iface,
                       struct usb_host_interface *alts,
                       struct audioformat *fmt)
{
        struct usb_interface_descriptor *altsd = get_iface_desc(alts);

        /* if endpoint doesn't have pitch control, bail out */
        if (!(fmt->attributes & UAC_EP_CS_ATTR_PITCH_CONTROL))
                return 0;

        switch (altsd->bInterfaceProtocol) {
        case UAC_VERSION_1:
        default:
                return init_pitch_v1(chip, iface, alts, fmt);

        case UAC_VERSION_2:
                return init_pitch_v2(chip, iface, alts, fmt);
        }
}

/*
 * find a matching format and set up the interface
 */
static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
{
        struct usb_device *dev = subs->dev;
        struct usb_host_interface *alts;
        struct usb_interface_descriptor *altsd;
        struct usb_interface *iface;
        unsigned int ep, attr;
        int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK;
        int err;

        iface = usb_ifnum_to_if(dev, fmt->iface);
        if (WARN_ON(!iface))
                return -EINVAL;
        alts = &iface->altsetting[fmt->altset_idx];
        altsd = get_iface_desc(alts);
        if (WARN_ON(altsd->bAlternateSetting != fmt->altsetting))
                return -EINVAL;

        if (fmt == subs->cur_audiofmt)
                return 0;

        /* close the old interface */
        if (subs->interface >= 0 && subs->interface != fmt->iface) {
                if (usb_set_interface(subs->dev, subs->interface, 0) < 0) {
                        snd_printk(KERN_ERR "%d:%d:%d: return to setting 0 failed\n",
                                dev->devnum, fmt->iface, fmt->altsetting);
                        return -EIO;
                }
                subs->interface = -1;
                subs->altset_idx = 0;
        }

        /* set interface */
        if (subs->interface != fmt->iface || subs->altset_idx != fmt->altset_idx) {
                if (usb_set_interface(dev, fmt->iface, fmt->altsetting) < 0) {
                        snd_printk(KERN_ERR "%d:%d:%d: usb_set_interface failed\n",
                                   dev->devnum, fmt->iface, fmt->altsetting);
                        return -EIO;
                }
                snd_printdd(KERN_INFO "setting usb interface %d:%d\n", fmt->iface, fmt->altsetting);
                subs->interface = fmt->iface;
                subs->altset_idx = fmt->altset_idx;
        }

        /* create a data pipe */
        ep = fmt->endpoint & USB_ENDPOINT_NUMBER_MASK;
        if (is_playback)
                subs->datapipe = usb_sndisocpipe(dev, ep);
        else
                subs->datapipe = usb_rcvisocpipe(dev, ep);
        subs->datainterval = fmt->datainterval;
        subs->syncpipe = subs->syncinterval = 0;
        subs->maxpacksize = fmt->maxpacksize;
        subs->syncmaxsize = 0;
        subs->fill_max = 0;

        /* we need a sync pipe in async OUT or adaptive IN mode */
        /* check the number of EP, since some devices have broken
         * descriptors which fool us.  if it has only one EP,
         * assume it as adaptive-out or sync-in.
         */
        attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;
        if (((is_playback && attr == USB_ENDPOINT_SYNC_ASYNC) ||
             (! is_playback && attr == USB_ENDPOINT_SYNC_ADAPTIVE)) &&
            altsd->bNumEndpoints >= 2) {
                /* check sync-pipe endpoint */
                /* ... and check descriptor size before accessing bSynchAddress
                   because there is a version of the SB Audigy 2 NX firmware lacking
                   the audio fields in the endpoint descriptors */
                if ((get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) != 0x01 ||
                    (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
                     get_endpoint(alts, 1)->bSynchAddress != 0)) {
                        snd_printk(KERN_ERR "%d:%d:%d : invalid synch pipe\n",
                                   dev->devnum, fmt->iface, fmt->altsetting);
                        return -EINVAL;
                }
                ep = get_endpoint(alts, 1)->bEndpointAddress;
                if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
                    (( is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
                     (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
                        snd_printk(KERN_ERR "%d:%d:%d : invalid synch pipe\n",
                                   dev->devnum, fmt->iface, fmt->altsetting);
                        return -EINVAL;
                }
                ep &= USB_ENDPOINT_NUMBER_MASK;
                if (is_playback)
                        subs->syncpipe = usb_rcvisocpipe(dev, ep);
                else
                        subs->syncpipe = usb_sndisocpipe(dev, ep);
                if (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
                    get_endpoint(alts, 1)->bRefresh >= 1 &&
                    get_endpoint(alts, 1)->bRefresh <= 9)
                        subs->syncinterval = get_endpoint(alts, 1)->bRefresh;
                else if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)
                        subs->syncinterval = 1;
                else if (get_endpoint(alts, 1)->bInterval >= 1 &&
                         get_endpoint(alts, 1)->bInterval <= 16)
                        subs->syncinterval = get_endpoint(alts, 1)->bInterval - 1;
                else
                        subs->syncinterval = 3;
                subs->syncmaxsize = le16_to_cpu(get_endpoint(alts, 1)->wMaxPacketSize);
        }

        /* always fill max packet size */
        if (fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX)
                subs->fill_max = 1;

        if ((err = snd_usb_init_pitch(subs->stream->chip, subs->interface, alts, fmt)) < 0)
                return err;

        subs->cur_audiofmt = fmt;

        snd_usb_set_format_quirk(subs, fmt);

#if 0
        printk(KERN_DEBUG
               "setting done: format = %d, rate = %d..%d, channels = %d\n",
               fmt->format, fmt->rate_min, fmt->rate_max, fmt->channels);
        printk(KERN_DEBUG
               "  datapipe = 0x%0x, syncpipe = 0x%0x\n",
               subs->datapipe, subs->syncpipe);
#endif

        return 0;
}

/*
 * hw_params callback
 *
 * allocate a buffer and set the given audio format.
 *
 * so far we use a physically linear buffer although packetize transfer
 * doesn't need a continuous area.
 * if sg buffer is supported on the later version of alsa, we'll follow
 * that.
 */
static int snd_usb_hw_params(struct snd_pcm_substream *substream,
                             struct snd_pcm_hw_params *hw_params)
{
        struct snd_usb_substream *subs = substream->runtime->private_data;
        struct audioformat *fmt;
        unsigned int channels, rate, format;
        int ret, changed;

        ret = snd_pcm_lib_alloc_vmalloc_buffer(substream,
                                               params_buffer_bytes(hw_params));
        if (ret < 0)
                return ret;

        format = params_format(hw_params);
        rate = params_rate(hw_params);
        channels = params_channels(hw_params);
        fmt = find_format(subs, format, rate, channels);
        if (!fmt) {
                snd_printd(KERN_DEBUG "cannot set format: format = %#x, rate = %d, channels = %d\n",
                           format, rate, channels);
                return -EINVAL;
        }

        changed = subs->cur_audiofmt != fmt ||
                subs->period_bytes != params_period_bytes(hw_params) ||
                subs->cur_rate != rate;
        if ((ret = set_format(subs, fmt)) < 0)
                return ret;

        if (subs->cur_rate != rate) {
                struct usb_host_interface *alts;
                struct usb_interface *iface;
                iface = usb_ifnum_to_if(subs->dev, fmt->iface);
                alts = &iface->altsetting[fmt->altset_idx];
                ret = snd_usb_init_sample_rate(subs->stream->chip, subs->interface, alts, fmt, rate);
                if (ret < 0)
                        return ret;
                subs->cur_rate = rate;
        }

        if (changed) {
                mutex_lock(&subs->stream->chip->shutdown_mutex);
                /* format changed */
                snd_usb_release_substream_urbs(subs, 0);
                /* influenced: period_bytes, channels, rate, format, */
                ret = snd_usb_init_substream_urbs(subs, params_period_bytes(hw_params),
                                                  params_rate(hw_params),
                                                  snd_pcm_format_physical_width(params_format(hw_params)) *
                                                        params_channels(hw_params));
                mutex_unlock(&subs->stream->chip->shutdown_mutex);
        }

        return ret;
}

/*
 * hw_free callback
 *
 * reset the audio format and release the buffer
 */
static int snd_usb_hw_free(struct snd_pcm_substream *substream)
{
        struct snd_usb_substream *subs = substream->runtime->private_data;

        subs->cur_audiofmt = NULL;
        subs->cur_rate = 0;
        subs->period_bytes = 0;
        mutex_lock(&subs->stream->chip->shutdown_mutex);
        snd_usb_release_substream_urbs(subs, 0);
        mutex_unlock(&subs->stream->chip->shutdown_mutex);
        return snd_pcm_lib_free_vmalloc_buffer(substream);
}

/*
 * prepare callback
 *
 * only a few subtle things...
 */
static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct snd_usb_substream *subs = runtime->private_data;

        if (! subs->cur_audiofmt) {
                snd_printk(KERN_ERR "usbaudio: no format is specified!\n");
                return -ENXIO;
        }

        /* some unit conversions in runtime */
        subs->maxframesize = bytes_to_frames(runtime, subs->maxpacksize);
        subs->curframesize = bytes_to_frames(runtime, subs->curpacksize);

        /* reset the pointer */
        subs->hwptr_done = 0;
        subs->transfer_done = 0;
        subs->phase = 0;
        subs->last_delay = 0;
        subs->last_frame_number = 0;
        runtime->delay = 0;

        return snd_usb_substream_prepare(subs, runtime);
}

static struct snd_pcm_hardware snd_usb_hardware =
{
        .info =                 SNDRV_PCM_INFO_MMAP |
                                SNDRV_PCM_INFO_MMAP_VALID |
                                SNDRV_PCM_INFO_BATCH |
                                SNDRV_PCM_INFO_INTERLEAVED |
                                SNDRV_PCM_INFO_BLOCK_TRANSFER |
                                SNDRV_PCM_INFO_PAUSE,
        .buffer_bytes_max =     1024 * 1024,
        .period_bytes_min =     64,
        .period_bytes_max =     512 * 1024,
        .periods_min =          2,
        .periods_max =          1024,
};

static int hw_check_valid_format(struct snd_usb_substream *subs,
                                 struct snd_pcm_hw_params *params,
                                 struct audioformat *fp)
{
        struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
        struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
        struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
        struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
        struct snd_mask check_fmts;
        unsigned int ptime;

        /* check the format */
        snd_mask_none(&check_fmts);
        check_fmts.bits[0] = (u32)fp->formats;
        check_fmts.bits[1] = (u32)(fp->formats >> 32);
        snd_mask_intersect(&check_fmts, fmts);
        if (snd_mask_empty(&check_fmts)) {
                hwc_debug("   > check: no supported format %d\n", fp->format);
                return 0;
        }
        /* check the channels */
        if (fp->channels < ct->min || fp->channels > ct->max) {
                hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
                return 0;
        }
        /* check the rate is within the range */
        if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
                hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
                return 0;
        }
        if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
                hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
                return 0;
        }
        /* check whether the period time is >= the data packet interval */
        if (snd_usb_get_speed(subs->dev) != USB_SPEED_FULL) {
                ptime = 125 * (1 << fp->datainterval);
                if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
                        hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
                        return 0;
                }
        }
        return 1;
}

static int hw_rule_rate(struct snd_pcm_hw_params *params,
                        struct snd_pcm_hw_rule *rule)
{
        struct snd_usb_substream *subs = rule->private;
        struct list_head *p;
        struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
        unsigned int rmin, rmax;
        int changed;

        hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
        changed = 0;
        rmin = rmax = 0;
        list_for_each(p, &subs->fmt_list) {
                struct audioformat *fp;
                fp = list_entry(p, struct audioformat, list);
                if (!hw_check_valid_format(subs, params, fp))
                        continue;
                if (changed++) {
                        if (rmin > fp->rate_min)
                                rmin = fp->rate_min;
                        if (rmax < fp->rate_max)
                                rmax = fp->rate_max;
                } else {
                        rmin = fp->rate_min;
                        rmax = fp->rate_max;
                }
        }

        if (!changed) {
                hwc_debug("  --> get empty\n");
                it->empty = 1;
                return -EINVAL;
        }

        changed = 0;
        if (it->min < rmin) {
                it->min = rmin;
                it->openmin = 0;
                changed = 1;
        }
        if (it->max > rmax) {
                it->max = rmax;
                it->openmax = 0;
                changed = 1;
        }
        if (snd_interval_checkempty(it)) {
                it->empty = 1;
                return -EINVAL;
        }
        hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
        return changed;
}


static int hw_rule_channels(struct snd_pcm_hw_params *params,
                            struct snd_pcm_hw_rule *rule)
{
        struct snd_usb_substream *subs = rule->private;
        struct list_head *p;
        struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
        unsigned int rmin, rmax;
        int changed;

        hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
        changed = 0;
        rmin = rmax = 0;
        list_for_each(p, &subs->fmt_list) {
                struct audioformat *fp;
                fp = list_entry(p, struct audioformat, list);
                if (!hw_check_valid_format(subs, params, fp))
                        continue;
                if (changed++) {
                        if (rmin > fp->channels)
                                rmin = fp->channels;
                        if (rmax < fp->channels)
                                rmax = fp->channels;
                } else {
                        rmin = fp->channels;
                        rmax = fp->channels;
                }
        }

        if (!changed) {
                hwc_debug("  --> get empty\n");
                it->empty = 1;
                return -EINVAL;
        }

        changed = 0;
        if (it->min < rmin) {
                it->min = rmin;
                it->openmin = 0;
                changed = 1;
        }
        if (it->max > rmax) {
                it->max = rmax;
                it->openmax = 0;
                changed = 1;
        }
        if (snd_interval_checkempty(it)) {
                it->empty = 1;
                return -EINVAL;
        }
        hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
        return changed;
}

static int hw_rule_format(struct snd_pcm_hw_params *params,
                          struct snd_pcm_hw_rule *rule)
{
        struct snd_usb_substream *subs = rule->private;
        struct list_head *p;
        struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
        u64 fbits;
        u32 oldbits[2];
        int changed;

        hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
        fbits = 0;
        list_for_each(p, &subs->fmt_list) {
                struct audioformat *fp;
                fp = list_entry(p, struct audioformat, list);
                if (!hw_check_valid_format(subs, params, fp))
                        continue;
                fbits |= fp->formats;
        }

        oldbits[0] = fmt->bits[0];
        oldbits[1] = fmt->bits[1];
        fmt->bits[0] &= (u32)fbits;
        fmt->bits[1] &= (u32)(fbits >> 32);
        if (!fmt->bits[0] && !fmt->bits[1]) {
                hwc_debug("  --> get empty\n");
                return -EINVAL;
        }
        changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
        hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
        return changed;
}

static int hw_rule_period_time(struct snd_pcm_hw_params *params,
                               struct snd_pcm_hw_rule *rule)
{
        struct snd_usb_substream *subs = rule->private;
        struct audioformat *fp;
        struct snd_interval *it;
        unsigned char min_datainterval;
        unsigned int pmin;
        int changed;

        it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
        hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
        min_datainterval = 0xff;
        list_for_each_entry(fp, &subs->fmt_list, list) {
                if (!hw_check_valid_format(subs, params, fp))
                        continue;
                min_datainterval = min(min_datainterval, fp->datainterval);
        }
        if (min_datainterval == 0xff) {
                hwc_debug("  --> get empty\n");
                it->empty = 1;
                return -EINVAL;
        }
        pmin = 125 * (1 << min_datainterval);
        changed = 0;
        if (it->min < pmin) {
                it->min = pmin;
                it->openmin = 0;
                changed = 1;
        }
        if (snd_interval_checkempty(it)) {
                it->empty = 1;
                return -EINVAL;
        }
        hwc_debug("  --> (%u,%u) (changed = %d)\n", it->min, it->max, changed);
        return changed;
}

/*
 *  If the device supports unusual bit rates, does the request meet these?
 */
static int snd_usb_pcm_check_knot(struct snd_pcm_runtime *runtime,
                                  struct snd_usb_substream *subs)
{
        struct audioformat *fp;
        int count = 0, needs_knot = 0;
        int err;

        list_for_each_entry(fp, &subs->fmt_list, list) {
                if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)
                        return 0;
                count += fp->nr_rates;
                if (fp->rates & SNDRV_PCM_RATE_KNOT)
                        needs_knot = 1;
        }
        if (!needs_knot)
                return 0;

        subs->rate_list.list = kmalloc(sizeof(int) * count, GFP_KERNEL);
        if (!subs->rate_list.list)
                return -ENOMEM;
        subs->rate_list.count = count;
        subs->rate_list.mask = 0;
        count = 0;
        list_for_each_entry(fp, &subs->fmt_list, list) {
                int i;
                for (i = 0; i < fp->nr_rates; i++)
                        subs->rate_list.list[count++] = fp->rate_table[i];
        }
        err = snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
                                         &subs->rate_list);
        if (err < 0)
                return err;

        return 0;
}


/*
 * set up the runtime hardware information.
 */

static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
{
        struct list_head *p;
        unsigned int pt, ptmin;
        int param_period_time_if_needed;
        int err;

        runtime->hw.formats = subs->formats;

        runtime->hw.rate_min = 0x7fffffff;
        runtime->hw.rate_max = 0;
        runtime->hw.channels_min = 256;
        runtime->hw.channels_max = 0;
        runtime->hw.rates = 0;
        ptmin = UINT_MAX;
        /* check min/max rates and channels */
        list_for_each(p, &subs->fmt_list) {
                struct audioformat *fp;
                fp = list_entry(p, struct audioformat, list);
                runtime->hw.rates |= fp->rates;
                if (runtime->hw.rate_min > fp->rate_min)
                        runtime->hw.rate_min = fp->rate_min;
                if (runtime->hw.rate_max < fp->rate_max)
                        runtime->hw.rate_max = fp->rate_max;
                if (runtime->hw.channels_min > fp->channels)
                        runtime->hw.channels_min = fp->channels;
                if (runtime->hw.channels_max < fp->channels)
                        runtime->hw.channels_max = fp->channels;
                if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
                        /* FIXME: there might be more than one audio formats... */
                        runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
                                fp->frame_size;
                }
                pt = 125 * (1 << fp->datainterval);
                ptmin = min(ptmin, pt);
        }
        err = snd_usb_autoresume(subs->stream->chip);
        if (err < 0)
                return err;

        param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
        if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)
                /* full speed devices have fixed data packet interval */
                ptmin = 1000;
        if (ptmin == 1000)
                /* if period time doesn't go below 1 ms, no rules needed */
                param_period_time_if_needed = -1;
        snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_TIME,
                                     ptmin, UINT_MAX);

        if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
                                       hw_rule_rate, subs,
                                       SNDRV_PCM_HW_PARAM_FORMAT,
                                       SNDRV_PCM_HW_PARAM_CHANNELS,
                                       param_period_time_if_needed,
                                       -1)) < 0)
                goto rep_err;
        if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
                                       hw_rule_channels, subs,
                                       SNDRV_PCM_HW_PARAM_FORMAT,
                                       SNDRV_PCM_HW_PARAM_RATE,
                                       param_period_time_if_needed,
                                       -1)) < 0)
                goto rep_err;
        if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
                                       hw_rule_format, subs,
                                       SNDRV_PCM_HW_PARAM_RATE,
                                       SNDRV_PCM_HW_PARAM_CHANNELS,
                                       param_period_time_if_needed,
                                       -1)) < 0)
                goto rep_err;
        if (param_period_time_if_needed >= 0) {
                err = snd_pcm_hw_rule_add(runtime, 0,
                                          SNDRV_PCM_HW_PARAM_PERIOD_TIME,
                                          hw_rule_period_time, subs,
                                          SNDRV_PCM_HW_PARAM_FORMAT,
                                          SNDRV_PCM_HW_PARAM_CHANNELS,
                                          SNDRV_PCM_HW_PARAM_RATE,
                                          -1);
                if (err < 0)
                        goto rep_err;
        }
        if ((err = snd_usb_pcm_check_knot(runtime, subs)) < 0)
                goto rep_err;
        return 0;

rep_err:
        snd_usb_autosuspend(subs->stream->chip);
        return err;
}

static int snd_usb_pcm_open(struct snd_pcm_substream *substream, int direction)
{
        struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct snd_usb_substream *subs = &as->substream[direction];

        subs->interface = -1;
        subs->altset_idx = 0;
        runtime->hw = snd_usb_hardware;
        runtime->private_data = subs;
        subs->pcm_substream = substream;
        /* runtime PM is also done there */
        return setup_hw_info(runtime, subs);
}

static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
{
        struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
        struct snd_usb_substream *subs = &as->substream[direction];

        if (!as->chip->shutdown && subs->interface >= 0) {
                usb_set_interface(subs->dev, subs->interface, 0);
                subs->interface = -1;
        }
        subs->pcm_substream = NULL;
        snd_usb_autosuspend(subs->stream->chip);
        return 0;
}

static int snd_usb_playback_open(struct snd_pcm_substream *substream)
{
        return snd_usb_pcm_open(substream, SNDRV_PCM_STREAM_PLAYBACK);
}

static int snd_usb_playback_close(struct snd_pcm_substream *substream)
{
        return snd_usb_pcm_close(substream, SNDRV_PCM_STREAM_PLAYBACK);
}

static int snd_usb_capture_open(struct snd_pcm_substream *substream)
{
        return snd_usb_pcm_open(substream, SNDRV_PCM_STREAM_CAPTURE);
}

static int snd_usb_capture_close(struct snd_pcm_substream *substream)
{
        return snd_usb_pcm_close(substream, SNDRV_PCM_STREAM_CAPTURE);
}

static struct snd_pcm_ops snd_usb_playback_ops = {
        .open =         snd_usb_playback_open,
        .close =        snd_usb_playback_close,
        .ioctl =        snd_pcm_lib_ioctl,
        .hw_params =    snd_usb_hw_params,
        .hw_free =      snd_usb_hw_free,
        .prepare =      snd_usb_pcm_prepare,
        .trigger =      snd_usb_substream_playback_trigger,
        .pointer =      snd_usb_pcm_pointer,
        .page =         snd_pcm_lib_get_vmalloc_page,
        .mmap =         snd_pcm_lib_mmap_vmalloc,
};

static struct snd_pcm_ops snd_usb_capture_ops = {
        .open =         snd_usb_capture_open,
        .close =        snd_usb_capture_close,
        .ioctl =        snd_pcm_lib_ioctl,
        .hw_params =    snd_usb_hw_params,
        .hw_free =      snd_usb_hw_free,
        .prepare =      snd_usb_pcm_prepare,
        .trigger =      snd_usb_substream_capture_trigger,
        .pointer =      snd_usb_pcm_pointer,
        .page =         snd_pcm_lib_get_vmalloc_page,
        .mmap =         snd_pcm_lib_mmap_vmalloc,
};

void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
{
        snd_pcm_set_ops(pcm, stream,
                        stream == SNDRV_PCM_STREAM_PLAYBACK ?
                        &snd_usb_playback_ops : &snd_usb_capture_ops);
}