Tuesday, October 19, 2010, 1:13:03 PM, you wrote: > Am Dienstag, 19. Oktober 2010, 11:42:09 schrieb Sander Eikelenboom: >> I was wondering why a USB2 device connected to a USB3 host controller causes much more interrupts then the same device on a USB2 controller. >> Probably because there isn't a seperate roothub handling the USB2 devices ? >> >> usb2 controller >> idle (no application grabbing video): 30 interrupts/second >> active (application grabbing video): 155 interrupts/second >> >> usb3 controller >> idle (no application grabbing video): 20 inter/second >> active (application grabbing video): 7830 inter/second > The ehci driver goes to great lengths to minimize the number of interrupts. > What you are seeing here is likely simply one interrupt per URB. > Regards > Oliver But it's the same application, grabbing the same videostream with the same settings from the same device, so the bandwidth used by the device should be the same for both Would it be expected that in such a case a usb3 controller would use more interrupts/URB's to transfer the same data ? -- 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
