Re: [PATCH v2 2/6] PCI/MSI: Factor out pci_get_msi_cap() interface

From: Alexander Gordeev
Date: Fri Sep 06 2013 - 09:15:52 EST


On Thu, Sep 05, 2013 at 05:40:41PM +0200, Alexander Gordeev wrote:
> On Thu, Sep 05, 2013 at 11:04:42AM -0400, Tejun Heo wrote:
> > The thing is, do we even have cases where arch code returns positive
> > return to indicate possible partial allocation? If not, the whole
> > interface is convoluted for no good reason and we can just make
> > everything return 0 or -errno, which is a lot simpler. No?
>
> As I mentioned in my other note, at least PPC has a concept of MSI quota,
> so exceeding it would be the very case, I believe.

An update here. No other arch supports multiple MSIs besides Intel (+IOMMU).
Yet, ironically, the concept of possible partial allocation was adopted from
MSI-X. I briefly checked all archs and it seems none of them throws out a
possible other number of MSIs > 1 (including PPC I mistakenly read).

--
Regards,
Alexander Gordeev
agordeev@xxxxxxxxxx
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