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From: Andi Kleen <ak@suse.de>
To: Alan Cox <alan@redhat.com>
Cc: torvalds@osdl.org, discuss@x86-64.org, akpm@osdl.org,
	markh@osdl.org, linux-scsi@vger.kernel.org, axboe@suse.de
Subject: Re: [PATCH] [29/82] x86_64: Rename IOMMU option, fix help and mark option embedded.
Date: Sun, 25 Jun 2006 21:32:41 +0200	[thread overview]
Message-ID: <200606252132.41121.ak@suse.de> (raw)
In-Reply-To: <20060625190054.GA6570@devserv.devel.redhat.com>

On Sunday 25 June 2006 21:00, Alan Cox wrote:
> On Sun, Jun 25, 2006 at 05:22:23PM +0200, Andi Kleen wrote:
> > > Older aacraid hardware cannot address the 3-4GB range where the iommu
> > > remaps pages. As the PCI DMA implementation for the x86-64 is flawed and
> > > doesn't support any nice way to deal with this via swiotlb instead the
> > > driver handles it internally.
> > 
> > Then you should just force a low bounce pfn < 0xfffffff for the block device - 
> > then the block layer  should use GFP_DMA bouncing.
> 
> From a tiny 16MB DMA pool that can't sustain the required load ? Or has that
> bit changed.

It should be ok because it blocks. It will be slow, but what else do you expect
from broken hardware like this? 

-Andi

  reply	other threads:[~2006-06-25 19:39 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-06-24  0:19 [PATCH] [29/82] x86_64: Rename IOMMU option, fix help and mark option embedded Andi Kleen
2006-06-24 23:14 ` Alan Cox
2006-06-25 15:22   ` Andi Kleen
2006-06-25 19:00     ` Alan Cox
2006-06-25 19:32       ` Andi Kleen [this message]
2006-06-25 22:21         ` Alan Cox
2006-06-26  6:24           ` Andi Kleen
  -- strict thread matches above, loose matches on Subject: below --
2006-06-26 12:37 Salyzyn, Mark

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