Re: [BK PATCH] USB update for 2.6.3

Linus Torvalds
2004-02-20T15:10:31Z

On Thu, 19 Feb 2004, David S. Miller wrote:
> On Fri, 20 Feb 2004 18:10:41 +1100
> Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
>
> > Hrm... so if the USB device drivers are actually doing the dma mapping
> > themselves, it make sense for them to pass their own struct device, no ?
>
> That's right, at least that was the idea.

No. That would be _fundamentally_ wrong.

There's no way a USB device can do DMA in the first place. It has no DMA
controller, and no way to read/write memory except through the USB host.

So it is the host - and only the host - that matters. Anything else is a
bug.

Linus