Re: usbmon, usb core, ARM

[David Brownell <david-b@pacbell.net>]

On Thursday 20 January 2005 11:35 am, Pete Zaitcev wrote:
> On Wed, 19 Jan 2005 09:08:34 -0800, David Brownell <david-b@pacbell.net> wrote:
> 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.

We have no reason to suspect bugs there; if there were any,
lots of things would have been breaking for a long time now.


> 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) {

Actually it'd be more like dev_is_root_hub(dev, bus), since
both values are readily at hand -- you're basically just
wanting to wrap "dev == hcd->self.root_hub" in most cases.
Though I'm still not clear why you'd want to change that
working code; nothing's broken now, after all.


By the way ... on the topic of usbmon rather than changing
usbcore, is there a brief writeup of what you want this
new version to be doing -- and how?  Like, why put the
spy hooks in that location, rather than any of the other
choices.  (Many of them would be less surprising to me!)

- Dave


>      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
>