4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lassi Ylikojola <lassi.ylikojola@xxxxxxxxx> commit 5e35dc0338d85ccebacf3f77eca1e5dea73155e8 upstream. Add quirk to ensure a sync endpoint is properly configured. This patch is a fix for same symptoms on Behringer UFX1204 as patch from Albertto Aquirre on Dec 8 2016 for Axe-Fx II. Signed-off-by: Lassi Ylikojola <lassi.ylikojola@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- sound/usb/pcm.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/sound/usb/pcm.c +++ b/sound/usb/pcm.c @@ -357,6 +357,15 @@ static int set_sync_ep_implicit_fb_quirk alts = &iface->altsetting[1]; goto add_sync_ep; + case USB_ID(0x1397, 0x0002): + ep = 0x81; + iface = usb_ifnum_to_if(dev, 1); + + if (!iface || iface->num_altsetting == 0) + return -EINVAL; + + alts = &iface->altsetting[1]; + goto add_sync_ep; } if (attr == USB_ENDPOINT_SYNC_ASYNC &&