On Thu, 10 May 2012, NeilBrown wrote: > Maybe we need to not suspend the USB OTG interface when the device as a > whole enters suspend-to-RAM. Maybe we need to register a dummy gadget to > the bus active while in suspend? > Does the gadget have to be responsive while-ever the bus is not suspended? Yes. > Maybe we can arrange for any USB activity to trigger a resume? Probably not, at least, not fast enough. The gadget is required to respond to USB packets within a few microseconds. At a minimum, the USB device controller would have to remain fully powered. > Entering suspend while still charging really should be possible - at least > with a dump charger and hopefully from a host port as well. I'll like to > find the best way to achieve that, and any help you can provide would be > greatly appreciated. If the gadget is attached to a dumb charger rather than a host then there's no problem. But otherwise it's not so simple. Have you read the USB charger class specification? (I haven't...) 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
