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Message-Id: <20100302.055534.115500087.davem@davemloft.net>
Date: Tue, 02 Mar 2010 05:55:34 -0800 (PST)
From: David Miller <davem@...emloft.net>
To: arnd@...db.de
Cc: fujita.tomonori@....ntt.co.jp, sparclinux@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] sparc: use asm-generic/scatterlist.h
From: Arnd Bergmann <arnd@...db.de>
Date: Tue, 2 Mar 2010 14:54:11 +0100
> Broken in the sense that arch/powerpc/Kconfig describes CONFIG_IOMMU_VMERGE:
>
> Cause IO segments sent to a device for DMA to be merged virtually
> by the IOMMU when they happen to have been allocated contiguously.
> This doesn't add pressure to the IOMMU allocator. However, some
> drivers don't support getting large merged segments coming back
> from *_map_sg().
>
> Most drivers don't have this problem; it is safe to say Y here.
>
> I don't know if this comment still applies to any drivers in the mainline
> kernel, but it's possible.
That really has to be out of date these days.
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