Re: usbmon, usb core, ARM

[Pete Zaitcev <zaitcev@redhat.com>]

On Wed, 19 Jan 2005 09:08:34 -0800, David Brownell <david-b@pacbell.net> wrote:

> On Wednesday 19 January 2005 7:42 am, Pete Zaitcev wrote:
> > 		Relying on pipe makes
> > tests dependant on URB only. No references to bus or HCD, therefore no
> > extra refcounts or worries about oopses. Also, HC drivers zero out the
> > urb->dev in giveback sequence which is a royal pain when trying to identify
> > a root hub.
> 
> That was a 2.4-ism, it should now be gone.  So an inlined function to
> test whether urb->dev is the root hub should suffice; I know there's
> code that does that already.

I do not like to refer to a dev because I do not quite understand where
the necessary usb_dev_get/_put are now. But if you guarantee that the
urb->dev is refcounted properly while urb is processed by usb_hcd_giveback_urb,
I do not mind an extra indirection.

What would be the right test in usb_hcd_giveback_urb, then?
It looks to me that you want me to use this:

urb_is_for_root_hub(urb) {
     return urb->dev == urb->dev->bus->hcpriv->self.root_hub;
}

This is just ... ewwwww. Can we use pipe for now or do you have
a better idea?

-- Pete