From: Grant Grundler <grundler@dsl2.external.hp.com>
To: Ryan Bradetich <rbradetich@uswest.net>
Cc: parisc-linux@lists.parisc-linux.org
Subject: Re: [parisc-linux] [PATCH] highmem_io for the sym53c8xx_2 driver??
Date: Sat, 23 Nov 2002 19:13:57 -0700 [thread overview]
Message-ID: <20021124021357.0EDBA482E@dsl2.external.hp.com> (raw)
In-Reply-To: Message from Ryan Bradetich <rbradetich@uswest.net> of "23 Nov 2002 00:38:26 MST." <1038037106.14815.4.camel@beavis>
Ryan Bradetich wrote:
...
> I am not sure what the highmem_io flag does, but when it is enabled it
> causes my C200 to HPMC.
That's for the SCSI midlayer to know whether or not the driver can do
64-bit DMA or not. Basically it means SCSI will use "page+offset"
instead of "address" when building SG lists.
All parisc machines require 32-bit DMA - ie through an IO MMU or direct.
Failures with highmem_io enabled suggests we aren't handling
"page+offset" correctly in the iommu code.
grant
next prev parent reply other threads:[~2002-11-24 2:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-11-23 7:38 [parisc-linux] [PATCH] highmem_io for the sym53c8xx_2 driver?? Ryan Bradetich
2002-11-24 2:13 ` Grant Grundler [this message]
2002-11-24 2:43 ` Grant Grundler
2002-11-25 18:59 ` Ryan Bradetich
2002-11-26 15:07 ` jsoe0708
2002-11-26 18:45 ` Grant Grundler
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