On Tue, Jul 27, 2010 at 10:40:53AM +0800, bradhuang wrote: > > Dears, > The usb 1.1 webcam can not work behind usb 2.0 hub when there is a usb 1.1 > mouse behind the hub, too. That is true, sometimes there just isn't enough bandwidth to do this. > We check ehci driver in ehci-sched.c , the "tt_available" function will > return 0 since "multi-uframe xfer can't fit in frame 7 uframe 0" , hence, > ISO pipe can NOT submit urb successfully > Do you have any idea about: > Is it the constrain in USB application? i.e. user can not use usb1.1 web cam > and mouse behind usb 2.0 hub simultaneously? Possibly yes. It's just not possible if you do the math involved. > Is there any bug fix about this kind of issues? Use multiple root hubs, plugging each device into their own. sorry, greg k-h -- 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
