It would be nice to have an option for PTP as well, but it doesn't make sense to have it as part of the enum, since you might want "ptp or alt", or "ptp or script"Rather than make it a menu choice, why not add something that can be enable / disabled via ptp command ?
I think it's more of a user preference than a PTP client thing. Making client store the setting and send it every time they connect seems round about. With a menu options, scripts can also set it using set_config_val if needed
The other issue I forgot to mention in my first post is how we detect "ptp connection". In reality we only have the USB bit, and whether the USB remote is masking it (get_usb_bit_physw).