USB HID defines a good number of power/battery telemetry/control items. It's bothered me a lot that no battery pack or chargers expose themselves as such in actual USB.
This whole series of resistors in usb legacy and aux channel chat in usb-pd makes me more than a bit sad. I would have liked to have used longstanding usb hid specs to implememt usb-pd, rather than having assorted side-band negotiations.
It still leaves the question of how two laptops would work. The naive "wait to see if there's a device and if not become the device" strategy more or less mirrors what usb-pd already does, with all the weird uncontrollable quirks. Im not sure how usb4 figures out there is a host-to-host link & negotiates networking, that's another wrinkle that might give us a good extension point to build from to enable bidirectional control. Maybe we run usb-ip over the network link - expose our usb hid battery/charger devices over that! ;p
This whole series of resistors in usb legacy and aux channel chat in usb-pd makes me more than a bit sad. I would have liked to have used longstanding usb hid specs to implememt usb-pd, rather than having assorted side-band negotiations.
It still leaves the question of how two laptops would work. The naive "wait to see if there's a device and if not become the device" strategy more or less mirrors what usb-pd already does, with all the weird uncontrollable quirks. Im not sure how usb4 figures out there is a host-to-host link & negotiates networking, that's another wrinkle that might give us a good extension point to build from to enable bidirectional control. Maybe we run usb-ip over the network link - expose our usb hid battery/charger devices over that! ;p