From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: linux-ide@vger.kernel.org, Jeff Garzik <jgarzik@pobox.com>,
Tejun Heo <htejun@gmail.com>
Subject: Re: libata and DMA quirks
Date: Fri, 27 Jun 2008 18:51:43 +1000 [thread overview]
Message-ID: <1214556703.8011.531.camel@pasglop> (raw)
In-Reply-To: <4864A6C9.2050709@ru.mvista.com>
On Fri, 2008-06-27 at 12:37 +0400, Sergei Shtylyov wrote:
> Hello.
>
> Benjamin Herrenschmidt wrote:
> > The main one is that one their latest cell, they do the following
> > "workarounds" which I never implemented in drivers/ide/ppc/pmac.c but
> > I'd like to implement in the libata driver, unless you believe that is
> > unnecessary:
> >
> > a) For any ATAPI DMA, If the transfer size is not a multiple of 16
> > bytes, switch to PIO for this command.
> >
>
> No need to do this in old driver anyway since the *IDE* core only
> uses DMA for block commands like READ and WRITE.
> Not sure about libata.
It doesn't use DMA to transfer the bulk of ATAPI ? I know it uses PIO
for the CDB but the rest of the transfer isn't done with DMA ?
Ben.
next prev parent reply other threads:[~2008-06-27 9:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-27 6:41 libata and DMA quirks Benjamin Herrenschmidt
2008-06-27 8:37 ` Sergei Shtylyov
2008-06-27 8:51 ` Benjamin Herrenschmidt [this message]
2008-06-27 9:10 ` Sergei Shtylyov
2008-06-27 9:31 ` Benjamin Herrenschmidt
2008-06-27 8:54 ` Alan Cox
2008-06-27 9:29 ` Benjamin Herrenschmidt
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