@@ -108,6 +108,7 @@ struct snd_usb_endpoint {
int iface, altsetting;
int skip_packets; /* quirks for devices to ignore the first n packets
in a stream */
+ bool is_implicit_feedback; /* This endpoint is used as implicit feedback */
spinlock_t lock;
struct list_head list;
@@ -522,6 +522,8 @@ struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
list_add_tail(&ep->list, &chip->ep_list);
+ ep->is_implicit_feedback = 0;
+
__exit_unlock:
mutex_unlock(&chip->mutex);
@@ -621,6 +623,178 @@ static void release_urbs(struct snd_usb_endpoint *ep, int force)
ep->nurbs = 0;
}
+/*
+ * Check data endpoint for format differences
+ */
+static bool check_ep_params(struct snd_usb_endpoint *ep,
+ snd_pcm_format_t pcm_format,
+ unsigned int channels,
+ unsigned int period_bytes,
+ unsigned int frames_per_period,
+ unsigned int periods_per_buffer,
+ struct audioformat *fmt,
+ struct snd_usb_endpoint *sync_ep)
+{
+ unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
+ unsigned int max_packs_per_period, urbs_per_period, urb_packs;
+ unsigned int max_urbs;
+ int frame_bits = snd_pcm_format_physical_width(pcm_format) * channels;
+ int tx_length_quirk = (ep->chip->tx_length_quirk &&
+ usb_pipeout(ep->pipe));
+ bool ret = 1;
+
+ if (pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
+ /*
+ * When operating in DSD DOP mode, the size of a sample frame
+ * in hardware differs from the actual physical format width
+ * because we need to make room for the DOP markers.
+ */
+ frame_bits += channels << 3;
+ }
+
+ ret = ret && (ep->datainterval == fmt->datainterval);
+ ret = ret && (ep->stride == frame_bits >> 3);
+
+ switch (pcm_format) {
+ case SNDRV_PCM_FORMAT_U8:
+ ret = ret && (ep->silence_value == 0x80);
+ break;
+ case SNDRV_PCM_FORMAT_DSD_U8:
+ case SNDRV_PCM_FORMAT_DSD_U16_LE:
+ case SNDRV_PCM_FORMAT_DSD_U32_LE:
+ case SNDRV_PCM_FORMAT_DSD_U16_BE:
+ case SNDRV_PCM_FORMAT_DSD_U32_BE:
+ ret = ret && (ep->silence_value == 0x69);
+ break;
+ default:
+ ret = ret && (ep->silence_value == 0);
+ }
+
+ /* assume max. frequency is 50% higher than nominal */
+ ret = ret && (ep->freqmax == ep->freqn + (ep->freqn >> 1));
+ /* Round up freqmax to nearest integer in order to calculate maximum
+ * packet size, which must represent a whole number of frames.
+ * This is accomplished by adding 0x0.ffff before converting the
+ * Q16.16 format into integer.
+ * In order to accurately calculate the maximum packet size when
+ * the data interval is more than 1 (i.e. ep->datainterval > 0),
+ * multiply by the data interval prior to rounding. For instance,
+ * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
+ * frames with a data interval of 1, but 11 (10.25) frames with a
+ * data interval of 2.
+ * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
+ * maximum datainterval value of 3, at USB full speed, higher for
+ * USB high speed, noting that ep->freqmax is in units of
+ * frames per packet in Q16.16 format.)
+ */
+ maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
+ (frame_bits >> 3);
+ if (tx_length_quirk)
+ maxsize += sizeof(__le32); /* Space for length descriptor */
+ /* but wMaxPacketSize might reduce this */
+ if (ep->maxpacksize && ep->maxpacksize < maxsize) {
+ /* whatever fits into a max. size packet */
+ unsigned int data_maxsize = maxsize = ep->maxpacksize;
+
+ if (tx_length_quirk)
+ /* Need to remove the length descriptor to calc freq */
+ data_maxsize -= sizeof(__le32);
+ ret = ret && (ep->freqmax == (data_maxsize / (frame_bits >> 3))
+ << (16 - ep->datainterval));
+ }
+
+ if (ep->fill_max)
+ ret = ret && (ep->curpacksize == ep->maxpacksize);
+ else
+ ret = ret && (ep->curpacksize == maxsize);
+
+ if (snd_usb_get_speed(ep->chip->dev) != USB_SPEED_FULL) {
+ packs_per_ms = 8 >> ep->datainterval;
+ max_packs_per_urb = MAX_PACKS_HS;
+ } else {
+ packs_per_ms = 1;
+ max_packs_per_urb = MAX_PACKS;
+ }
+ if (sync_ep && !snd_usb_endpoint_implicit_feedback_sink(ep))
+ max_packs_per_urb = min(max_packs_per_urb,
+ 1U << sync_ep->syncinterval);
+ max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
+
+ /*
+ * Capture endpoints need to use small URBs because there's no way
+ * to tell in advance where the next period will end, and we don't
+ * want the next URB to complete much after the period ends.
+ *
+ * Playback endpoints with implicit sync much use the same parameters
+ * as their corresponding capture endpoint.
+ */
+ if (usb_pipein(ep->pipe) ||
+ snd_usb_endpoint_implicit_feedback_sink(ep)) {
+
+ urb_packs = packs_per_ms;
+ /*
+ * Wireless devices can poll at a max rate of once per 4ms.
+ * For dataintervals less than 5, increase the packet count to
+ * allow the host controller to use bursting to fill in the
+ * gaps.
+ */
+ if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_WIRELESS) {
+ int interval = ep->datainterval;
+
+ while (interval < 5) {
+ urb_packs <<= 1;
+ ++interval;
+ }
+ }
+ /* make capture URBs <= 1 ms and smaller than a period */
+ urb_packs = min(max_packs_per_urb, urb_packs);
+ while (urb_packs > 1 && urb_packs * maxsize >= period_bytes)
+ urb_packs >>= 1;
+ ret = ret && (ep->nurbs == MAX_URBS);
+
+ /*
+ * Playback endpoints without implicit sync are adjusted so that
+ * a period fits as evenly as possible in the smallest number of
+ * URBs. The total number of URBs is adjusted to the size of the
+ * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
+ */
+ } else {
+ /* determine how small a packet can be */
+ minsize = (ep->freqn >> (16 - ep->datainterval)) *
+ (frame_bits >> 3);
+ /* with sync from device, assume it can be 12% lower */
+ if (sync_ep)
+ minsize -= minsize >> 3;
+ minsize = max(minsize, 1u);
+
+ /* how many packets will contain an entire ALSA period? */
+ max_packs_per_period = DIV_ROUND_UP(period_bytes, minsize);
+
+ /* how many URBs will contain a period? */
+ urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
+ max_packs_per_urb);
+ /* how many packets are needed in each URB? */
+ urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
+
+ /* limit the number of frames in a single URB */
+ ret = ret && (ep->max_urb_frames ==
+ DIV_ROUND_UP(frames_per_period, urbs_per_period));
+
+ /* try to use enough URBs to contain an entire ALSA buffer */
+ max_urbs = min((unsigned) MAX_URBS,
+ MAX_QUEUE * packs_per_ms / urb_packs);
+ ret = ret && (ep->nurbs == min(max_urbs,
+ urbs_per_period * periods_per_buffer));
+ }
+
+ ret = ret && (ep->datainterval == fmt->datainterval);
+ ret = ret && (ep->maxpacksize == fmt->maxpacksize);
+ ret = ret &&
+ (ep->fill_max == !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX));
+
+ return ret;
+}
+
/*
* configure a data endpoint
*/
@@ -886,10 +1060,23 @@ int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
int err;
if (ep->use_count != 0) {
- usb_audio_warn(ep->chip,
- "Unable to change format on ep #%x: already in use\n",
- ep->ep_num);
- return -EBUSY;
+ bool check = ep->is_implicit_feedback &&
+ check_ep_params(ep, pcm_format,
+ channels, period_bytes,
+ period_frames, buffer_periods,
+ fmt, sync_ep);
+
+ if (!check) {
+ usb_audio_warn(ep->chip,
+ "Unable to change format on ep #%x: already in use\n",
+ ep->ep_num);
+ return -EBUSY;
+ }
+
+ usb_audio_dbg(ep->chip,
+ "Ep #%x already in use as implicit feedback but format not changed\n",
+ ep->ep_num);
+ return 0;
}
/* release old buffers, if any */
@@ -386,6 +386,8 @@ add_sync_ep:
if (!subs->sync_endpoint)
return -EINVAL;
+ subs->sync_endpoint->is_implicit_feedback = 1;
+
subs->data_endpoint->sync_master = subs->sync_endpoint;
return 1;
@@ -484,12 +486,15 @@ static int set_sync_endpoint(struct snd_usb_substream *subs,
implicit_fb ?
SND_USB_ENDPOINT_TYPE_DATA :
SND_USB_ENDPOINT_TYPE_SYNC);
+
if (!subs->sync_endpoint) {
if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
return 0;
return -EINVAL;
}
+ subs->sync_endpoint->is_implicit_feedback = implicit_fb;
+
subs->data_endpoint->sync_master = subs->sync_endpoint;
return 0;