Re: Reworking suspend-resume sequence (was: Re: PCI PM: Restore standard config registers of all devices early)

Linus Torvalds
2009-02-03T21:20:15Z

On Tue, 3 Feb 2009, Ingo Molnar wrote:
>
> So i'd still like your tentative Signed-off-by for your patch - it's i think
> not v2.6.29 material but if it stays problem free in testing we can try it
> in v2.6.30. If it causes problem it will be clearly bisectable and clearly
> revertable.

Hmm. You can have my sign-off, because I certainly don't think the patch
is _wrong_, but I also don't think it's necessarily really worth it unless
somebody can show a real upside. As mentioned, I don't think this matters
in practice for the whole MSI suspend issue - doing the "mask()" thing
feels stupid and certainl;y wasn't what I expected us to do, but it really
shouldn't matter from an actual behavioural standpoint at all.

And if, as you say, we don't expect to have interrupts spread out across
CPUs (and with the current io-apic they certainly don't happen - I don't
know about x2apic) my performance arguments are bogus too.

So the patch probably is the right thing to do, but the upsides are slim
to nonexistent, and the downside you pointed out of somebody using that
"handle_edge_irq()" thing with an interrupt that turns out to be level
after all makes me worry a bit.

But feel free to put it in some experimental branch with my sign-off.

Linus