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From: James Bottomley <James.Bottomley@steeleye.com>
To: Jeremy Higdon <jeremy@sgi.com>
Cc: Andrew Morton <akpm@osdl.org>,
	willy@debian.org, Jes Sorensen <jes@wildopensource.com>,
	Grant Grundler <grundler@parisc-linux.org>,
	alex.williamson@hp.com, jbarnes@sgi.com, ak@muc.de,
	Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] move consistent_dma_mask to the generic device
Date: 27 Feb 2004 08:55:30 -0600	[thread overview]
Message-ID: <1077893732.1806.2.camel@mulgrave> (raw)
In-Reply-To: <20040227065702.GB561561@sgi.com>

On Fri, 2004-02-27 at 00:57, Jeremy Higdon wrote:
> I haven't had a chance to try it yet, but it looks good.
> 
> If you're going to get rid of pci_dev.consistent_dma_mask in favor
> of pci_dev.dev.coherent_dma_mask, would you want to do the same
> with pci_dev.dma_mask?

It's probably about time that was done, yes.

> Which brings to mind a second question; why is device.dma_mask
> a u64 * instead of u64?  Does it typically point to pci_dev.dma_mask?

That's a bad design decision that will forever haunt me.  When I first
proposed moving from the PCI DMA model to the generic device DMA model,
the dma_mask was in the wrong place.  Quite a few drivers touched it
themselves outside of the accessor functions, so actually moving it in
to struct device became quite involved, so I took the easy way out and
simply made the entry in struct device a pointer to the real one so that
anything that updated the mask outside of the accessors would still
work.

I suppose I should really do the work as pennance, plus write out a
hundred times "never sacrifice design integrity for expediency", sigh.

James



      reply	other threads:[~2004-02-27 14:56 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-02-26 16:53 [PATCH] move consistent_dma_mask to the generic device James Bottomley
2004-02-27  6:57 ` Jeremy Higdon
2004-02-27 14:55   ` James Bottomley [this message]

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