Re: [Libusb-devel] using /dev/bus/usb vs. /proc/bus/usb

[Linus W. <tr...@df...>]

On Thu, 1 Jun 2006, Tim Roberts wrote:

[answers as seen from my point of view]

> Perhaps someone can help me understand this little better.  I happen to
> be using a Ubuntu system, which uses /proc/bus/usb.  I naïvely thought
> this was the "latest and greatest" in USB support.

No that's actually old. The latest and greatest is to not even mount 
/proc/bus/usb and use udev exclusively to create device nodes under /dev 
(where they ought to be). However removing that is usually not wise for 
distributions.

> On those FC5
> systems, does /dev/bus/usb have the same functionality?

Yes it is supposed to be a 1-to-1 mapping of the stuff previously in 
/proc/bus/usb.

>  That is, is
> there a "devices" file, and files like "004/003" with a default driver
> that responds to the same ioctls that my /proc/bus/usb device responds to?

Yes.

> In summary, is that just "usbfs" but mounted at a different root?

No, it is not usbfs. It is ordinary device files, just created in a 
directory hierarchy under /dev that has the same layout as it used to 
have in /proc. There are even a few things /proc/bus/usb can do which 
/dev/bus/usb can't, but it's quite esoteric so I don't know the exact 
details...

Linus