From: Jeff Garzik <jgarzik@pobox.com>
To: Russell King <rmk+lkml@arm.linux.org.uk>
Cc: Takashi Iwai <tiwai@suse.de>,
Matt Porter <mporter@kernel.crashing.org>,
Jamey Hicks <jamey.hicks@hp.com>, Ian Molton <spyro@f2s.com>,
linux-kernel@vger.kernel.org, greg@kroah.com, tony@atomide.com,
david-b@pacbell.net, joshua@joshuawise.com,
Linus Torvalds <torvalds@osdl.org>
Subject: Re: DMA API issues
Date: Mon, 21 Jun 2004 22:06:23 -0400 [thread overview]
Message-ID: <40D7941F.3020909@pobox.com> (raw)
In-Reply-To: <20040622000838.B7802@flint.arm.linux.org.uk>
Russell King wrote:
> On Mon, Jun 21, 2004 at 03:35:42PM +0200, Takashi Iwai wrote:
>>Yes, the struct page pointer is needed for vma_ops.nopage in mmap on
>>ALSA. So far, this is broken on some architectures like ARM. We need
>>a proper conversion from virtual/bus pointer to a page struct.
>
>
> Please get away from your nopage implementation. We've been around this
> before with Linus, and the conclusion was that it's up to architectures
> to provide a MMAP method for DMA memory, which _may_ use the nopage
> method if and only if it is appropriate for their implementation.
Can you elaborate?
When I was writing sound/oss/via82cxxx_audio.c, Linus specifically
recommended using ->nopage, which worked out quite well (modulo cleaning
up VM_xxx flags).
Jeff
next prev parent reply other threads:[~2004-06-22 2:07 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-06-18 16:59 DMA API issues 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 [this message]
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
-- strict thread matches above, loose matches on Subject: below --
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
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
2004-06-18 19:30 ` 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
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