Allow power without data

[vincentbernat]

Hey!

When a device is not authorized, the bMax attribute in sysfs is empty. The device will draw only 100mA in this configuration. Authorizing the device puts 500mA (in case of a Sony headset) and the device can draw 500mA (if authorized soon enough, otherwise, I suppose it stopped trying to get more).

Would it be possible to authorize a device for power, but not for data. I didn't find such a possibility in the Linux kernel documentation, so maybe not.

[muelli]

good question.
Sounds like something to bring up with the Linux people.

[Lukas1811]

I would guess that's not possible, since you need to allow the BC traffic on the data lines, therefore you need to allow the device, otherwise this communication is ignored (but I'm not a USB nor Linux expert, so maybe there is a way to do it).