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

From: Tejun Heo
Date: Thu Sep 26 2013 - 10:42:16 EST


Hello,

On Thu, Sep 26, 2013 at 10:39 AM, Alexander Gordeev <agordeev@xxxxxxxxxx> wrote:
> I can imagine a scenario where the first device probes in, requests its

Well, we can imagine a lot of thing but usually have to draw the line somewhere.

> optimal number, acquires that number and exhausts MSIs in pSeries firmware.
> The next few devices possibly end up with single MSI, since no MSIs left
> to satisfy their optimal numbers. If one of those single-MSI'ed devices
> happened to be a high-performance HBA hitting a degraded performance that
> alone would force (IBM) to introduce the quotas. Now, if the same/another
> device happened does not support the legacy interrupt mode and no MSI
> resources have left in the platform firmware at all...

If that happens, that's just the platform code being dumb. Quota is
there to prevent that from happening, right? Let's please do something
simple and worry about problems if they actually exist.

Thanks.

--
tejun
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