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Date: Wed, 18 Sep 2013 00:30:23 +1000
From: Michael Ellerman <michael@ellerman.id.au>
To: Alexander Gordeev <agordeev@redhat.com>
Subject: Re: [PATCH v2 2/6] PCI/MSI: Factor out pci_get_msi_cap() interface
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Cc: linuxppc-dev@lists.ozlabs.org, Joerg Roedel <joro@8bytes.org>,
 "x86@kernel.org" <x86@kernel.org>,
 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
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 "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
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On Mon, Sep 16, 2013 at 12:22:11PM +0200, Alexander Gordeev wrote:
> On Mon, Sep 09, 2013 at 05:20:44PM +0200, Alexander Gordeev wrote:
> > On Fri, Sep 06, 2013 at 05:32:05PM -0600, Bjorn Helgaas wrote:
> > > I propose that you rework it that way, and at least find out what
> > > (if anything) would break if we do that.  Or maybe we just give up
> > > some optimization; it would be nice to quantify that, too.
> > 
> > Hi Bjorn,
> > 
> > The series is what it seems a direction to take.
> > 
> > Looks like we need PPC folks to agree on the quota check update
> > for pSeries (yes, they do bail out with a positive return value
> > from arch_msi_check_device()):
> 
> Hi Ben,
> 
> An initiative to simplify MSI/MSI-X allocation interface is brewing.
> It seems pSeries quota thing is an obstacle. If it could be given up
> (patch 2/9).

How about no?

We have a small number of MSIs available, limited by hardware &
firmware, if we don't impose a quota then the first device that probes
will get most/all of the MSIs and other devices miss out.

Anyway I don't see what problem you're trying to solve? I agree the
-ve/0/+ve return value pattern is ugly, but it's hardly the end of the
world.

cheers