From: Jeff Garzik <jgarzik@mandrakesoft.com>
To: Steffen Persvold <sp@scali.no>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
Helge Hafting <helgehaf@idb.hist.no>,
Vasu Varma P V <pvvvarma@techmas.hcltech.com>,
linux-kernel@vger.kernel.org,
"David S. Miller" <davem@redhat.com>
Subject: Re: DMA memory limitation?
Date: Fri, 06 Jul 2001 11:39:57 -0400 [thread overview]
Message-ID: <3B45DBCD.76B27634@mandrakesoft.com> (raw)
In-Reply-To: <E15ITTf-0004Dz-00@the-village.bc.nu> <3B45A08D.408D56@mandrakesoft.com> <3B45D656.440A34A9@scali.no>
Steffen Persvold wrote:
> > pci_alloc_* is designed to support ISA.
> >
> > Pass pci_dev==NULL to pci_alloc_* for ISA devices, and it allocs GFP_DMA
> > for you.
> Sure, but the IA64 platforms that are out now doesn't have an IOMMU, so bounce buffers are
> used if you don't specify GFP_DMA in your get_free_page.
[...]
> (pci_alloc_consistent() allocates a buffer with GFP_DMA on IA64),
The important thing is that pci_alloc_consistent and the other PCI DMA
functions work as advertised on IA64. If you pass NULL to
pci_alloc_consistent, IA64 should give you an ISA DMA-able address. If
you don't, you get a 32-bit PCI DMA address. Use of GFP_DMA is a
arch-specific detail, so don't let me confuse you there.
--
Jeff Garzik | A recent study has shown that too much soup
Building 1024 | can cause malaise in laboratory mice.
MandrakeSoft |
next prev parent reply other threads:[~2001-07-06 15:40 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-07-05 11:47 DMA memory limitation? Vasu Varma P V
2001-07-05 11:53 ` Alan Cox
2001-07-05 11:54 ` Arjan van de Ven
2001-07-05 12:37 ` Vasu Varma P V
2001-07-05 12:37 ` Richard B. Johnson
2001-07-05 17:07 ` Christophe Beaumont
2001-07-05 17:19 ` Richard B. Johnson
2001-07-06 8:59 ` Helge Hafting
2001-07-06 9:44 ` Steffen Persvold
2001-07-06 11:08 ` Alan Cox
2001-07-06 11:27 ` Jeff Garzik
2001-07-06 15:16 ` Steffen Persvold
2001-07-06 15:39 ` Jeff Garzik [this message]
2001-07-06 15:48 ` Alan Cox
-- strict thread matches above, loose matches on Subject: below --
2001-07-06 15:56 Matt_Domsch
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