On Tue, 10 Jun 2014, Grant wrote: > >> Understood. Can you tell me how to disable VBUS on the USB > >> hub/controller? I'll be attempting this on a Beaglebone. > > > > I don't know what controller the Beaglebone uses. In general, however, > > it isn't possible to disable Vbus on a USB host port and still use the > > port. To do what you want, you would have to physically cut the Vbus > > wire in the USB cable and splice the device side of that wire to the > > external power supply. > > USB cables like that do exist for sale. Is there a way to disable > VBUS on the host port if I use a cable like that? Like I said before, if you did manage to disable Vbus on the host port, the port would be unusable -- even with a separate power source for the device. The hardware in some controllers will allow port power to be switched off and the hardware in others won't. I don't know whether the Beaglebone's controller does. For the ones that do, probably the easiest way to turn off the power is to use my hubpower program: http://marc.info/?l=linux-usb&m=127162615232234&w=2 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
