From: Linus Torvalds <torvalds@osdl.org>
To: "David S. Miller" <davem@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
greg@kroah.com, akpm@osdl.org,
linux-usb-devel@lists.sourceforge.net,
linux-kernel@vger.kernel.org
Subject: Re: [BK PATCH] USB update for 2.6.3
Date: Fri, 20 Feb 2004 07:15:31 -0800 (PST) [thread overview]
Message-ID: <Pine.LNX.4.58.0402200714270.1107@ppc970.osdl.org> (raw)
In-Reply-To: <20040219233214.56f5b0ce.davem@redhat.com>
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
next prev parent reply other threads:[~2004-02-20 15:10 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-02-20 1:28 Greg KH
2004-02-20 5:58 ` Linus Torvalds
2004-02-20 6:03 ` Benjamin Herrenschmidt
2004-02-20 6:30 ` Linus Torvalds
2004-02-20 6:28 ` Benjamin Herrenschmidt
2004-02-20 6:47 ` Linus Torvalds
2004-02-20 6:42 ` Benjamin Herrenschmidt
2004-02-20 7:00 ` Greg KH
2004-02-20 7:06 ` Benjamin Herrenschmidt
2004-02-20 7:58 ` [linux-usb-devel] " David Brownell
2004-02-20 7:03 ` Linus Torvalds
2004-02-20 7:04 ` David S. Miller
2004-02-20 7:10 ` Benjamin Herrenschmidt
2004-02-20 7:32 ` David S. Miller
2004-02-20 15:15 ` Linus Torvalds [this message]
2004-02-20 18:15 ` Hollis Blanchard
2004-02-20 18:39 ` Linus Torvalds
2004-02-20 19:20 ` Hollis Blanchard
2004-02-20 19:32 ` Linus Torvalds
2004-02-20 22:40 ` [linux-usb-devel] " Benjamin Herrenschmidt
2004-02-20 19:30 ` Alan Stern
2004-02-20 7:08 ` Benjamin Herrenschmidt
2004-02-20 8:08 ` David Brownell
2004-02-20 9:26 ` Russell King
2004-02-20 7:40 ` Deepak Saxena
2004-02-20 7:47 ` [linux-usb-devel] " Benjamin Herrenschmidt
2004-02-20 8:08 ` Deepak Saxena
2004-02-20 8:43 ` David Brownell
2004-02-20 8:48 ` Benjamin Herrenschmidt
2004-02-20 9:27 ` Russell King
[not found] <fa.d7mjamc.1l40pri@ifi.uio.no>
2004-02-20 6:34 ` Andy Lutomirski
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