From: Jens Axboe <axboe@suse.de>
To: Mark Lord <liml@rtr.ca>
Cc: Jeff Garzik <jgarzik@pobox.com>,
IDE/ATA development list <linux-ide@vger.kernel.org>,
James Bottomley <James.Bottomley@steeleye.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: libata+SGIO: is .dma_boundary respected?
Date: Tue, 21 Mar 2006 20:35:38 +0100 [thread overview]
Message-ID: <20060321193538.GO4285@suse.de> (raw)
In-Reply-To: <44205525.20306@rtr.ca>
On Tue, Mar 21 2006, Mark Lord wrote:
> Mark Lord wrote:
> >Jeff Garzik wrote:
> >>
> >>>In the case of sata_mv on the Marvell 6081 (which I'm looking at this
> >>>week)
> >>>it's hardware limit is actually 0xffffffff rather than 0xffff.
> >>
> >>If the limit is not 0xffff, then there's no need for any of this
> >>limitation junk. No s/g entry splitting after pci_map_sg(), no
> >>artificial sg_tablesize limitation, etc.
> >
> >Not even for a merged IOMMU segment that crosses the 4GB "boundary" ?
>
> Clarification: this is a 64-bit PCI(e/X) device, and the above query
> applies mainly to it's use in a 64-bit slot on a 64-bit kernel.
>
> It's not clear to me whether this can be an issue on a 32-bit kernel
> on 36-bit hardware, though.
My explanation was for the block layer part of course, I'm hoping (did
not check) that the iommu has similar sane defaults.
But this still really wants a unification of the dma restrictions...
--
Jens Axboe
next prev parent reply other threads:[~2006-03-21 19:35 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-19 20:48 libata+SGIO: is .dma_boundary respected? Mark Lord
2006-03-19 21:14 ` Jeff Garzik
2006-03-19 21:19 ` Mark Lord
2006-03-19 21:38 ` Jeff Garzik
2006-03-19 21:45 ` Mark Lord
2006-03-19 21:54 ` Mark Lord
2006-03-21 1:18 ` Jeff Garzik
2006-03-21 4:43 ` Mark Lord
2006-03-21 6:14 ` Jeff Garzik
2006-03-21 13:59 ` Mark Lord
2006-03-21 18:42 ` Jens Axboe
2006-03-21 19:18 ` Mark Lord
2006-03-21 19:29 ` Jeff Garzik
2006-03-21 19:31 ` Mark Lord
2006-03-21 19:33 ` Mark Lord
2006-03-21 19:35 ` Jens Axboe [this message]
2006-03-21 19:38 ` Jeff Garzik
2006-03-21 19:42 ` Jens Axboe
2006-03-21 19:43 ` James Bottomley
2006-03-21 19:46 ` Jens Axboe
2006-03-21 20:44 ` James Bottomley
2006-03-21 21:54 ` Benjamin Herrenschmidt
2006-03-21 19:31 ` Jens Axboe
2006-03-21 19:36 ` Mark Lord
2006-03-21 19:43 ` Jeff Garzik
2006-03-21 20:51 ` Mark Lord
2006-03-22 11:25 ` Tejun Heo
2006-03-22 14:52 ` Mark Lord
2006-03-21 1:15 ` Jeff Garzik
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