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authorDaniel Mack <zonque@gmail.com>2012-04-12 13:51:14 +0200
committerTakashi Iwai <tiwai@suse.de>2012-04-13 10:24:32 +0200
commitc75a8a7ae565d7cd9baa87a504ba9162e355b4b0 (patch)
tree19d3158213cbdbec05a901a5e253871991a2609a /sound/usb
parentd399ff9593e088d33fb38f5206c6427825892baa (diff)
ALSA: snd-usb: add support for implicit feedback
Implicit feedback is a streaming mode that does not rely on dedicated sync endpoints but uses the information provided by record streams to clock output streams. Now that the streaming logic is decoupled from the PCM streams, this is easy to implement. Signed-off-by: Daniel Mack <zonque@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb')
-rw-r--r--sound/usb/pcm.c37
1 files changed, 26 insertions, 11 deletions
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 0f107834c100..2d3a04d829b7 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -301,7 +301,7 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
struct usb_interface *iface;
unsigned int ep, attr;
int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK;
- int err;
+ int err, implicit_fb = 0;
iface = usb_ifnum_to_if(dev, fmt->iface);
if (WARN_ON(!iface))
@@ -326,25 +326,34 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
* 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) {
- switch (subs->stream->chip->usb_id) {
- case USB_ID(0x0763, 0x2080): /* M-Audio FastTrack Ultra */
- case USB_ID(0x0763, 0x2081):
+
+ switch (subs->stream->chip->usb_id) {
+ case USB_ID(0x0763, 0x2080): /* M-Audio FastTrack Ultra */
+ case USB_ID(0x0763, 0x2081):
+ if (is_playback) {
+ implicit_fb = 1;
ep = 0x81;
iface = usb_ifnum_to_if(dev, 2);
+
+ if (!iface || iface->num_altsetting == 0)
+ return -EINVAL;
+
alts = &iface->altsetting[1];
goto add_sync_ep;
}
+ }
+ 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)) {
+ get_endpoint(alts, 1)->bSynchAddress != 0 &&
+ !implicit_fb)) {
snd_printk(KERN_ERR "%d:%d:%d : invalid synch pipe\n",
dev->devnum, fmt->iface, fmt->altsetting);
return -EINVAL;
@@ -352,16 +361,22 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
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)))) {
+ (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)) ||
+ ( is_playback && !implicit_fb))) {
snd_printk(KERN_ERR "%d:%d:%d : invalid synch pipe\n",
dev->devnum, fmt->iface, fmt->altsetting);
return -EINVAL;
}
+
+ implicit_fb = (get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_USAGE_MASK)
+ == USB_ENDPOINT_USAGE_IMPLICIT_FB;
+
add_sync_ep:
subs->sync_endpoint = snd_usb_add_endpoint(subs->stream->chip,
alts, ep, !subs->direction,
- SND_USB_ENDPOINT_TYPE_SYNC);
-
+ implicit_fb ?
+ SND_USB_ENDPOINT_TYPE_DATA :
+ SND_USB_ENDPOINT_TYPE_SYNC);
if (!subs->sync_endpoint)
return -EINVAL;