On Sat, 7 Jun 2014, Grant wrote: > >> Can I disable VBUS while keeping the rest of USB functional for a > >> device that does not require bus power? > > > > unfortunately not, your device would see a disconnection. The reason is > > that even though you don't really put any load on the bus, the PHY still > > samples VBUS levels to know when the session is valid (VBUS > 4.4V). > > What if I use a USB cable with a separate DC input for the VBUS? What would be the point? I mean, if you've got a separate DC input for Vbus then you aren't really saving any power or disabling anything. If you did this and then turned off the separate DC power, your device wouldn't work afterward. As Felipe pointed out, the device would think the cable had been disconnected. 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
