Re: Reboot resistant USB bug

[Iain Hibbert <plunky%ogmig.net@localhost>]

On Thu, 11 Oct 2018, Emmanuel Dreyfus wrote:

> Hello
> 
> On both netbsd-8 and -current, I have a problem with USB devices that
> get stuck in a non-functionning state even after a reboot.
> 
> This happens after interrupting transfer with different NFC readers 
> from different vendors, and the only way to recover the device is 
> to power-cycle it. I wonder if there could be a missing step in the 
> way we initialize USB devices that could explain that situation.

This is a 'state' issue which does not change unless the device is power 
cycled, which we do not generally do as part of the init AFAIK. I noticed 
this with Bluetooth adaptors many years ago and we issue a reset because 
of that but it doesn't affect the USB part of the device and adaptors 
sometimes do fail to restart on reboot.

What do other OSs do in this way?  It seems difficult to guess the state 
and we just assume that it is in post-cold boot when we attach which may 
not always be optimal.

iain