Re: [linux-usb-devel] Re: [BK PATCH] USB update for 2.6.3

[Deepak Saxena <dsaxena@plexity.net>]

On Feb 20 2004, at 18:47, Benjamin Herrenschmidt was caught saying:
> 
> > If you mean the USB target device itself, can't you walk the
> > tree until you find a device that is no longer on bus_type
> > usb to determine your root?
> 
> I don't feel like walking the tree on each pci_dma access

I never said it would be pretty. :)

> 
> > You could stuff that into platform_data on PCI devices on your platforms.
> 
> I want automatic inheritance to child devices, shouldb't be _that_
> difficult to do ;)

Hmm, I wonder if the easiet way to do this at the moment would be
to add a platform specific hook that gets called during device_add().
On arches that don't need to do this, it would just be a nop, but on 
PPC64 and others it could do whatever is required.  By the time that 
device_add() is called, it is already attached to a bus, so this 
function could walk the tree to inherit parameters at discovery time 
instead of the above suggestion. 

Seems doable without impacting other arches.

~Deepak

-- 
Deepak Saxena - dsaxena at plexity dot net - http://www.plexity.net/