On Thu, 4 Jul 2013, Clemens Ladisch wrote: > Alan Stern wrote: > > On Thu, 4 Jul 2013, Ming Lei wrote: > >>> Changing the altsetting is another way to tell the HCD that a stream is > >>> starting fresh. > >> > >> Yes, it might work, but many details need to be payed attention to, such > >> as, changing altsetting may not be done during suspend/resume. > > > > Hmmm. I don't know how snd-usb-audio handles a suspend/resume in the > > middle of playback or recording. > > In this case, the ALSA framework will stop the PCM stream, and on resume, > report this like an underrun; the application will then reinitialize the > stream. (Handling suspend/resume transparently would require that the > driver can restart playing from an arbitrary position in the ring buffer; > snd-usb-audio does not bother to implement this.) Good; that means we don't have to worry about it. :-) Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
