On Mon, 17 May 2010, Khanh-Dang Nguyen Thu Lam wrote: > > > ATM dev 0: usbatm_submit_urb: urb 0xcfa8abe0 submission failed (-28)! > > > > -28 is -ENOSPC, which means there is not enough bandwidth available on > > the USB bus for both devices to run at the same time. > > Strange. I don't expect a USB keyboard to be bandwidth-consuming. It is, because the system has to poll it constantly to see if any keys have been pressed or released. Even worse, because keyboards generally are low-speed devices, each bit requires as much bandwidth as 8 bits on a full-speed device. > Moreover, the same USB DSL modem works when doing a scan using a USB > scanner plugged in place of the USB keyboard. The scanner probably doesn't need to reserve any bandwidth. The keyboard does. 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
