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Subject: Re: qla_wxyz pci_set_mwi question
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Matthew Wilcox <matthew@wil.cx>
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Date: Fri, 13 Apr 2007 12:34:22 +1000
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Cc: Randy Dunlap <randy.dunlap@oracle.com>, scsi <linux-scsi@vger.kernel.org>,
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On Thu, 2007-04-12 at 14:04 -0600, Matthew Wilcox wrote:
> On Thu, Apr 12, 2007 at 12:37:13PM -0700, Andrew Vasquez wrote:
> > On Thu, 12 Apr 2007, Matthew Wilcox wrote:
> > > Why should it fail?  If there's a platform which can't support a
> > > cacheline size that the qla2xyz card can handle, it should be able to
> > > happily fall back to doing plain writes instead of MWIs.  IMO, it should
> > > just call pci_set_mwi() and ignore the result.
> > 
> > I believe there were some erratas on some ISP2xxx chips where MWI
> > needed to be set for proper operation.  I'll go back, verify and
> > update the patch accordingly.
> 
> Hmm.  The thing is that pci_set_mwi() returns success on machines where
> MWI is disabled (currently only PPC64).  Perhaps it needs to fail
> instead.

MWI isn't diabled on ppc64... or did I miss something ?

Ben.