diff options
Diffstat (limited to 'sound/usb/quirks.c')
| -rw-r--r-- | sound/usb/quirks.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c index acc12f004c2..2c971858d6b 100644 --- a/sound/usb/quirks.c +++ b/sound/usb/quirks.c @@ -387,11 +387,13 @@ static int snd_usb_fasttrackpro_boot_quirk(struct usb_device *dev) * rules */ err = usb_driver_set_configuration(dev, 2); - if (err < 0) { + if (err < 0) snd_printdd("error usb_driver_set_configuration: %d\n", err); - return -ENODEV; - } + /* Always return an error, so that we stop creating a device + that will just be destroyed and recreated with a new + configuration */ + return -ENODEV; } else snd_printk(KERN_INFO "usb-audio: Fast Track Pro config OK\n"); @@ -859,6 +861,17 @@ void snd_usb_endpoint_start_quirk(struct snd_usb_endpoint *ep) if ((le16_to_cpu(ep->chip->dev->descriptor.idVendor) == 0x23ba) && ep->type == SND_USB_ENDPOINT_TYPE_SYNC) ep->skip_packets = 4; + + /* + * M-Audio Fast Track C400 - when packets are not skipped, real world + * latency varies by approx. +/- 50 frames (at 96KHz) each time the + * stream is (re)started. When skipping packets 16 at endpoint start + * up, the real world latency is stable within +/- 1 frame (also + * across power cycles). + */ + if (ep->chip->usb_id == USB_ID(0x0763, 0x2030) && + ep->type == SND_USB_ENDPOINT_TYPE_DATA) + ep->skip_packets = 16; } void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe, |