Re: [PATCH] USB: add USB test and measurement class driver - round2

[Alan Stern]

On Wed, 27 Aug 2008, Oliver Neukum wrote:

> Am Mittwoch 27 August 2008 20:58:08 schrieb Alan Stern:
> > > And this rule depends on sharing the USB major or not. This needs
> > > a big fat mention in Documentation.
> > 
> > You mean that the open/disconnect locking rule applies only to drivers 
> > that call usb_register_dev, i.e, drivers using the USB major.  Right?
> 
> Yes. In fact drivers not using the USB major but their own char devices
> will need such a lock. This is tricky.

IMO all char-device registration/deregistration routines should use a 
similar rwsem.  Then device drivers wouldn't need to worry about it.

> > I agree that it deserves to be mentioned in the documentation 
> > somewhere.  Where would be a good place?  None of the existing files in 
> > Documentation/usb seem appropriate.
> 
> The USB major merits a file of its own.

I don't feel competent to start writing such a file.  Greg, what do you 
think?  Maybe all that's needed to get going is to "borrow" some of the 
material in LDD3.  :-)

Alan Stern

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