From: Arnd Bergmann <arnd@arndb.de>
To: Russell King <rmk+lkml@arm.linux.org.uk>
Subject: Re: [PATCH] asm-generic: add dma-mapping-linear.h
Date: Mon, 1 Jun 2009 12:42:21 +0100
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Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>,
       linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org
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On Monday 01 June 2009, Russell King wrote:

> I didn't say "for all architectures".  I said that the end conditions
> need to be the same no matter how DMA is done.
> 
> And yes, it does matter with some cache types.  VIPT aliasing caches
> and VIVT caches both need to ensure that condition is met, otherwise
> userspace doesn't see the data.

Ok, thanks for the explanation.

> While we can hand-wave and say "some other part of the code should
> handle this" I've had that disucssion several times, and that's where
> this requirement eventually was stated.  And, really, I'm not going
> to re-discuss it yet again - I really don't have time or motivation
> at present to be involved in yet another hand-waving egotistical
> debate over it.

I was not trying to start a debate over this, just being curious.

	Arnd <><
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