[Fwd: RE: cciss patches for 2.4.21-rc1, 4 of 4]

From: Arjan van de Ven (arjanv@redhat.com)
Date: Fri Apr 25 2003 - 09:29:15 EST


-----Forwarded Message-----

> From: Alan Cox <alan@lxorguk.ukuu.org.uk>
> To: "Miller, Mike (OS Dev)" <Mike.Miller@hp.com>
> Cc: "Cameron, Steve" <Steve.Cameron@hp.com>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
> Subject: RE: cciss patches for 2.4.21-rc1, 4 of 4
> Date: 25 Apr 2003 14:09:53 +0100
>
> On Gwe, 2003-04-25 at 14:48, Miller, Mike (OS Dev) wrote:
> > I haven't seen any issues (yet) on ia64. I'm running with 5GB RAM.
>
> That doesn't make it correct. This same problem occurs in other drivers
> and the usual trick is to set the pci mask to 32bit, allocate those
> command buffers ready, then flip back to 64bit. Just be sure one thread
> doesn't change it to 64bit while another is allocating commands. The
> reverse is fine since an accidental odd bounce is no big deal
Alan,

except that pci_alloc_consistent is guaranteed to return a 32 bit address

what you're thinking about is the mapping interface instead.



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