spin_lock_irqsave(&subs->lock, flags);
est_delay = snd_usb_pcm_delay(subs, runtime->rate);
/* update delay with exact number of samples played */
spin_lock_irqsave(&subs->lock, flags);
est_delay = snd_usb_pcm_delay(subs, runtime->rate);
/* update delay with exact number of samples played */