An implicit feedback endpoint can only be a capture source. The consumer (sink) of the implicit feedback endpoint is therefore limited to playback EPs. Check if the target endpoint is a playback first and remove redundant checks.
Signed-off-by: Eldad Zack eldad@fogrefinery.com --- sound/usb/pcm.c | 40 +++++++++++++++++++--------------------- 1 file changed, 19 insertions(+), 21 deletions(-)
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c index 8865833..c14cb78 100644 --- a/sound/usb/pcm.c +++ b/sound/usb/pcm.c @@ -334,41 +334,39 @@ static int set_sync_ep_implicit_fb_quirk(struct snd_usb_substream *subs, { struct usb_host_interface *alts; struct usb_interface *iface; - int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK; int implicit_fb = 0; unsigned int ep;
+ /* Implicit feedback sync EPs consumers are always playback EPs */ + if (subs->direction != SNDRV_PCM_STREAM_PLAYBACK) + return 0; + switch (subs->stream->chip->usb_id) { case USB_ID(0x0763, 0x2030): /* M-Audio Fast Track C400 */ case USB_ID(0x0763, 0x2031): /* M-Audio Fast Track C600 */ - if (is_playback) { - implicit_fb = 1; - ep = 0x81; - iface = usb_ifnum_to_if(dev, 3); + implicit_fb = 1; + ep = 0x81; + iface = usb_ifnum_to_if(dev, 3);
- if (!iface || iface->num_altsetting == 0) - return -EINVAL; + if (!iface || iface->num_altsetting == 0) + return -EINVAL;
- alts = &iface->altsetting[1]; - goto add_sync_ep; - } + alts = &iface->altsetting[1]; + goto add_sync_ep; break; 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); + implicit_fb = 1; + ep = 0x81; + iface = usb_ifnum_to_if(dev, 2);
- if (!iface || iface->num_altsetting == 0) - return -EINVAL; + if (!iface || iface->num_altsetting == 0) + return -EINVAL;
- alts = &iface->altsetting[1]; - goto add_sync_ep; - } + alts = &iface->altsetting[1]; + goto add_sync_ep; } - if (is_playback && - attr == USB_ENDPOINT_SYNC_ASYNC && + if (attr == USB_ENDPOINT_SYNC_ASYNC && altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC && altsd->bInterfaceProtocol == 2 && altsd->bNumEndpoints == 1 &&