From: Oliver Neukum <oliver@neukum.org>
To: James Bottomley <James.Bottomley@SteelEye.com>
Cc: Ian Molton <spyro@f2s.com>,
rmk+lkml@arm.linux.org.uk, david-b@pacbell.net,
Linux Kernel <linux-kernel@vger.kernel.org>,
greg@kroah.com, tony@atomide.com, jamey.hicks@hp.com,
joshua@joshuawise.com
Subject: Re: DMA API issues
Date: Sun, 20 Jun 2004 21:34:52 +0200 [thread overview]
Message-ID: <200406202134.58657.oliver@neukum.org> (raw)
In-Reply-To: <1087759622.10858.97.camel@mulgrave>
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Am Sonntag, 20. Juni 2004 21:27 schrieb James Bottomley:
> On Sun, 2004-06-20 at 13:02, Oliver Neukum wrote:
> > > The DMA API is about allowing devices to transact directly with memory
> > > behind the memory controller, it's an API that essentially allows the
> > > I/O controller and memory controller to communicate without CPU
> > > intervention. This is still possible through the hypervisor, so the
> > > iSeries currently fully implements the DMA API.
> >
> > Then what's the problem?
>
> If you look at the diagram, you'll see that the OHCI memory isn't behind
> the memory controller...
And that means what? We don't care about how memory is implemented
in the machines we run on. All we care about is the consequences of the
implementation.
We have an area of memory here that the CPU and a subset of devices
can directly access. What to do about it?
Regards
Oliver
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next prev parent reply other threads:[~2004-06-20 19:34 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-06-18 18:20 James Bottomley
2004-06-18 18:35 ` Ian Molton
2004-06-18 18:52 ` James Bottomley
2004-06-18 18:57 ` Ian Molton
2004-06-18 19:20 ` David Brownell
2004-06-18 19:44 ` Ian Molton
2004-06-18 19:57 ` James Bottomley
2004-06-18 21:08 ` David Brownell
2004-06-18 21:14 ` James Bottomley
2004-06-18 22:38 ` David Brownell
2004-06-18 23:07 ` James Bottomley
2004-06-18 23:31 ` Ian Molton
2004-06-19 18:23 ` David Brownell
2004-06-19 20:41 ` Russell King
2004-06-19 21:46 ` James Bottomley
2004-06-19 22:49 ` Ian Molton
2004-06-20 13:37 ` James Bottomley
2004-06-20 15:50 ` Ian Molton
2004-06-20 16:26 ` Jeff Garzik
2004-06-20 16:57 ` Ian Molton
2004-06-20 20:15 ` David Brownell
2004-06-20 16:46 ` James Bottomley
2004-06-20 18:02 ` Oliver Neukum
2004-06-20 19:27 ` James Bottomley
2004-06-20 19:34 ` Oliver Neukum [this message]
2004-06-20 20:07 ` David Brownell
2004-06-20 20:18 ` David Brownell
2004-06-20 20:02 ` David Brownell
2004-06-18 23:25 ` Ian Molton
2004-06-18 23:29 ` James Bottomley
2004-06-18 23:51 ` Ian Molton
2004-06-19 0:04 ` James Bottomley
2004-06-19 0:14 ` Ian Molton
2004-06-19 3:49 ` James Bottomley
2004-06-20 20:59 ` Jamey Hicks
2004-06-19 15:11 ` DMA API issues... summary Ian Molton
2004-06-20 20:49 ` Joshua Wise
2004-06-18 19:30 ` DMA API issues James Bottomley
2004-06-18 19:56 ` Ian Molton
2004-06-18 19:22 ` Jamey Hicks
2004-06-18 19:41 ` James Bottomley
2004-06-18 20:02 ` Oliver Neukum
2004-06-18 20:07 ` James Bottomley
2004-06-18 20:14 ` Benjamin Herrenschmidt
2004-06-18 20:24 ` James Bottomley
2004-06-18 21:20 ` Russell King
2004-06-18 23:20 ` Ian Molton
2004-06-20 18:25 ` Deepak Saxena
-- strict thread matches above, loose matches on Subject: below --
2004-06-18 16:59 Ian Molton
2004-06-18 18:07 ` Matt Porter
2004-06-18 18:19 ` Ian Molton
2004-06-18 18:58 ` Matt Porter
2004-06-18 18:33 ` Jamey Hicks
2004-06-18 19:21 ` Matt Porter
2004-06-18 19:43 ` Russell King
2004-06-21 13:35 ` Takashi Iwai
2004-06-21 23:08 ` Russell King
2004-06-22 2:06 ` Jeff Garzik
2004-06-22 3:18 ` Linus Torvalds
2004-06-22 3:26 ` Linus Torvalds
2004-06-22 10:40 ` Takashi Iwai
2004-06-23 12:34 ` Russell King
2004-06-23 15:36 ` Takashi Iwai
2004-06-23 15:44 ` Russell King
2004-06-23 16:01 ` Takashi Iwai
2004-06-23 16:10 ` Russell King
2004-06-22 10:48 ` Takashi Iwai
2004-06-18 19:48 ` Jamey Hicks
2004-06-18 21:08 ` Jeff Garzik
2004-06-18 22:12 ` Richard B. Johnson
2004-06-18 23:27 ` Ian Molton
2004-06-18 23:26 ` Ian Molton
2004-06-18 23:30 ` James Bottomley
2004-06-18 23:32 ` Jeff Garzik
[not found] ` <20040619005714.37b68453.spyro@f2s.com>
[not found] ` <40D3838B.2070608@pobox.com>
[not found] ` <20040619011621.4491600a.spyro@f2s.com>
[not found] ` <40D3872F.5010007@pobox.com>
2004-06-19 0:34 ` Ian Molton
2004-06-19 21:15 ` Tony Lindgren
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