USB stack / configuration 0

[Bernd Walter]

On Tue, Jan 06, 2004 at 12:43:20AM +0000, Jay Cornwall wrote:
> Hi
> 
> I've just finished a patch to alleviate several panics in the ugen driver 
> (related to devfs issues and setting a USB device's configuration to 
> USB_UNCONFIG_NO). I'm about to submit to freebsd-current@, but I need to 
> clarify something first.

Sounds great!

> When setting a USB device to configuration number USB_UNCONFIG_NO (i.e. 0), 
> the device goes into an unconfigured state with an invalid dev->cdesc. How 
> does one then leave this unconfigured state and reconfigure the device to 
> accept configuration changes? (all USB_SET_CONFIG changes are currently 
> refused after going into configuration 0 - I'm not sure if this is the 
> desired behaviour or a bug)

I have to read the docs first bevor making a qualified comment about
this.

> All I can think of is unplugging/plugging the device back in. In which 
> case, why would we want to let users set USB_UNCONFIG_NO in the first place?

You can always reset the hub port.
Nevertheless USB_UNCONFIG_NO shouldn't be allowed IMO - it can easily
happen by accident.

-- 
B.Walter                   BWCT                http://www.bwct.de
ticso at bwct.de                                  info at bwct.de