On Wed, 2 Oct 2013, Mauro Carvalho Chehab wrote: > > > So, there's no need to call usb_change_ep_bandwidth(). > > > > That's right. > > > > > If so, then usb_change_ep_bandwidth() as a quirk, if bInterval > > > or wMaxPacketSize were improperly filled. > > > > > > Right? > > > > Or if the values are correct, but the driver wants to use something > > different for its own reasons (for example, to get lower latency or > > because it knows that it will never use packets as large as the > > descriptor allows). Right. > > Ok, so, in this case, usb_change_ep_bandwidth() could be called > just before usb_alloc_urb(), in order to make it to use the packet > size that would be expected for that kind of ISOC traffic that > userspace indirectly selected, by adjusting the streaming > video resolution selected, right? We haven't decided on the final API yet. However, note that usb_alloc_urb() doesn't depend on the packet size. It requires you to specify only the number of packets, not their sizes. Therefore it doesn't matter whether you call usb_change_ep_bandwidth() before or after usb_alloc_urb(). 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
