Re: USB hotplug: knowing which interface you are being called for

[Greg KH <greg@kroah.com>]

On Wed, Feb 26, 2003 at 09:11:46PM +0100, Duncan Sands wrote:
> On Wednesday 26 February 2003 18:04, Greg KH wrote:
> > On Wed, Feb 26, 2003 at 04:39:36PM +0100, Duncan Sands wrote:
> > > Greetings hotpluggers: when a USB device is plugged in (2.5), the
> > > usb hotplugging scripts are called for each interface.  I don't see a
> > > convenient way to work out the interface number from the info passed
> > > it, namely the path to the interface in sysfs.  Any suggestions?
> >
> > As discussed on #kernelnewbies irc channel:
> > 	basename $DEVPATH
> > will give the interface number.  Hm, you might have to search that
> > result for a ":" and then use the number after that which is the
> > interface number.
> >
> > And I'll go add endpoint info to the sysfs directory too, that should
> > make your life easier, right?
> 
> Hi Greg, thanks for looking into this.  You are right about the ":" of course.
> It would be nice to have all the info about the interface present in the sysfs
> directory (yes, including the interface number!), i.e. the same info as in
> struct usb_interface.  This creates some kind of equality between probe
> methods and hotplugging scripts - and why not supply the info if it exists?

Ok, I just did that:
	http://linuxusb.bkbits.net:8080/usb-2.5/patch@1.1415

> For the endpoints, I guess you are going to have to deal with alternate
> interface settings as well.  I can see two methods: (1) a subdirectory for
> each alt setting, containing endpoints, (2) endpoints indexed by alt setting
> and endpoint number.

Yeah, the endpoints aren't going to be as simple, I'll have to think
about them for a bit.

> By the way, how are different configurations dealt with in the sysfs tree?

They really aren't supported well at all, see Oliver's patch a while ago
on linux-usb-devel that added better support to the core first.

thanks,

greg k-h


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