From: Russell King <rmk@arm.linux.org.uk>
To: davidm@hpl.hp.com
Cc: "David S. Miller" <davem@redhat.com>,
manfred@colorfullife.com, axboe@suse.de,
linux-kernel@vger.kernel.org
Subject: Re: problem with blk_queue_bounce_limit()
Date: Sat, 7 Jun 2003 10:44:34 +0100 [thread overview]
Message-ID: <20030607104434.B22665@flint.arm.linux.org.uk> (raw)
In-Reply-To: <16097.37454.827982.278024@napali.hpl.hp.com>; from davidm@napali.hpl.hp.com on Sat, Jun 07, 2003 at 12:20:46AM -0700
On Sat, Jun 07, 2003 at 12:20:46AM -0700, David Mosberger wrote:
> ./include/asm-arm/pci.h:#define PCI_DMA_BUS_IS_PHYS (0)
I suspect we probably set this incorrectly; we have some platforms where
there is merely an offset between the phys address and the bus address.
For these, I think we want to set this to 1.
Other platforms require the dma functions to allocate a new buffer
and copy the data to work around buggy "wont fix" errata (eg, new buffer
below 1MB) and for these I think we want to leave this at 0.
It is rather unfortunate that this got called "PCI_xxx" since it has
been used in a non pci-bus manner in (eg) the scsi layer.
Also note that I have platforms where the dma_mask is a real mask not
"a set of zeros followed by a set of ones from MSB to LSB." I can
see this breaking the block layer if PCI_DMA_BUS_IS_PHYS is defined
to one. 8/
--
Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux
http://www.arm.linux.org.uk/personal/aboutme.html
next prev parent reply other threads:[~2003-06-07 9:31 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-06-05 6:42 problem with blk_queue_bounce_limit() David Mosberger
2003-06-05 7:20 ` David S. Miller
2003-06-06 6:42 ` David Mosberger
2003-06-06 6:45 ` David S. Miller
2003-06-06 6:54 ` David Mosberger
2003-06-06 7:08 ` David S. Miller
2003-06-06 6:52 ` David S. Miller
2003-06-06 7:19 ` David Mosberger
2003-06-06 7:32 ` David S. Miller
2003-06-06 7:44 ` Christoph Hellwig
2003-06-06 7:43 ` David S. Miller
2003-06-06 7:51 ` Christoph Hellwig
2003-06-06 20:13 ` David Mosberger
2003-06-07 6:44 ` David S. Miller
2003-06-07 7:05 ` David Mosberger
2003-06-07 7:11 ` David S. Miller
2003-06-10 20:01 ` David Mosberger
2003-06-12 6:47 ` David S. Miller
2003-06-15 7:06 ` Anton Blanchard
2003-06-15 7:11 ` David S. Miller
2003-06-15 8:04 ` Anton Blanchard
2003-06-15 8:18 ` David S. Miller
2003-06-07 7:20 ` David Mosberger
2003-06-07 7:19 ` David S. Miller
2003-06-07 9:44 ` Russell King [this message]
2003-06-07 9:47 ` David S. Miller
2003-06-07 13:23 ` Christoph Hellwig
2003-06-10 20:24 ` David Mosberger
-- strict thread matches above, loose matches on Subject: below --
2003-06-06 18:06 James Bottomley
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