From: Ingo Molnar <mingo@elte.hu>
To: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: yinghai@kernel.org, hpa@zytor.com, tglx@linutronix.de,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86: fix gart iommu using for amd 64 bit system
Date: Wed, 25 Nov 2009 08:25:04 +0100 [thread overview]
Message-ID: <20091125072504.GA6568@elte.hu> (raw)
In-Reply-To: <20091125085730S.fujita.tomonori@lab.ntt.co.jp>
* FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> wrote:
> On Tue, 24 Nov 2009 16:26:45 +0100
> Ingo Molnar <mingo@elte.hu> wrote:
>
> >
> > * FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> wrote:
> >
> > > > don't think user will like to use SWIOTLB instead of swiotlb.
> > >
> > > I doubt that users care about a way to fix their problems.
> >
> > As far as swiotlb vs. GART goes, arguably a non-bouncing hw based
> > solution (GART) is superior to a bouncing one (swiotlb), right?
>
> Yeah, but GART is not a real IOMMU that always does address
> translation. If users want performance, they need 64bit DMA capable
> devices to skip GART. With such devices, GART and SWIOTLB are same.
>
> So this hacky GART workaround is useful for only people who use non
> 64bit DMA devices and broken BIOS with GART. IMO, it's not worth
> having the workaround.
Well, what Yinghai is saying that for that (nonzero) subset of people
this change is a regression, and his patch fixes that. We dont do
regressions so this needs to be addressed.
Thanks,
Ingo
next prev parent reply other threads:[~2009-11-25 7:47 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-10 10:46 [PATCH v2 0/9] x86: handle HW IOMMU initialization failure gracefully FUJITA Tomonori
2009-11-10 10:46 ` [PATCH -v2 1/9] add iommu_init to x86_init_ops FUJITA Tomonori
2009-11-10 13:22 ` [tip:core/iommu] x86: Add " tip-bot for FUJITA Tomonori
2009-11-10 13:42 ` [tip:core/iommu] x86: Add iommu_init to x86_init_ops, fix build tip-bot for Ingo Molnar
2009-11-10 10:46 ` [PATCH -v2 2/9] Calgary: convert detect_calgary to use iommu_init hook FUJITA Tomonori
2009-11-10 13:22 ` [tip:core/iommu] x86: Calgary: Convert detect_calgary() " tip-bot for FUJITA Tomonori
2009-11-10 10:46 ` [PATCH -v2 3/9] GART: convert gart_iommu_hole_init " FUJITA Tomonori
2009-11-10 13:23 ` [tip:core/iommu] x86: GART: Convert gart_iommu_hole_init() " tip-bot for FUJITA Tomonori
2009-11-10 10:46 ` [PATCH -v2 4/9] amd_iommu: convert amd_iommu_detect " FUJITA Tomonori
2009-11-10 13:23 ` [tip:core/iommu] x86: amd_iommu: Convert amd_iommu_detect() " tip-bot for FUJITA Tomonori
2009-11-10 10:46 ` [PATCH -v2 5/9] intel-iommu: convert detect_intel_iommu " FUJITA Tomonori
2009-11-10 11:12 ` Ingo Molnar
2009-11-10 13:23 ` [tip:core/iommu] x86: intel-iommu: Convert " tip-bot for FUJITA Tomonori
2009-11-10 10:46 ` [PATCH -v2 6/9] bootmem: add free_bootmem_late FUJITA Tomonori
2009-11-10 12:00 ` Johannes Weiner
2009-11-14 12:50 ` FUJITA Tomonori
2009-11-10 13:23 ` [tip:core/iommu] bootmem: Add free_bootmem_late() tip-bot for FUJITA Tomonori
2009-11-11 23:56 ` [PATCH -v2 6/9] bootmem: add free_bootmem_late Andrew Morton
2009-11-12 7:47 ` Ingo Molnar
2009-11-10 10:46 ` [PATCH -v2 7/9] swiotlb: add swiotlb_free function FUJITA Tomonori
2009-11-10 11:27 ` Ingo Molnar
2009-11-10 13:24 ` [tip:core/iommu] swiotlb: Add swiotlb_free() function tip-bot for FUJITA Tomonori
2009-11-10 10:46 ` [PATCH -v2 8/9] swiotlb: export swiotlb_print_info FUJITA Tomonori
2009-11-10 13:24 ` [tip:core/iommu] swiotlb: Defer swiotlb init printing, export swiotlb_print_info() tip-bot for FUJITA Tomonori
2009-11-10 10:46 ` [PATCH -v2 9/9] x86: handle HW IOMMU initialization failure gracely FUJITA Tomonori
2009-11-10 11:27 ` Ingo Molnar
2009-11-10 13:24 ` [tip:core/iommu] x86: Handle HW IOMMU initialization failure gracefully tip-bot for FUJITA Tomonori
2009-11-22 4:24 ` [PATCH] x86: fix gart iommu using for amd 64 bit system Yinghai Lu
2009-11-22 5:19 ` [PATCH] x86: fix gart iommu using for amd 64 bit system -v2 Yinghai Lu
2009-11-24 8:46 ` [PATCH] x86: fix gart iommu using for amd 64 bit system FUJITA Tomonori
2009-11-24 9:19 ` Yinghai Lu
2009-11-24 9:35 ` FUJITA Tomonori
2009-11-24 9:48 ` Yinghai Lu
2009-11-24 10:31 ` FUJITA Tomonori
2009-11-24 10:42 ` Yinghai Lu
2009-11-24 13:50 ` FUJITA Tomonori
2009-11-24 15:26 ` Ingo Molnar
2009-11-24 18:28 ` Yinghai Lu
2009-11-24 23:57 ` FUJITA Tomonori
2009-11-25 7:25 ` Ingo Molnar [this message]
2009-11-25 7:56 ` FUJITA Tomonori
2009-11-24 18:48 ` Yinghai Lu
2009-11-24 23:48 ` FUJITA Tomonori
2009-11-10 11:19 ` [PATCH v2 0/9] x86: handle HW IOMMU initialization failure gracefully Ingo Molnar
2009-11-10 11:55 ` Ingo Molnar
2009-11-10 12:35 ` FUJITA Tomonori
2009-11-22 3:17 ` Yinghai Lu
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