On Tue, 1 Nov 2011 13:50:13 -0400 (EDT) Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > On Tue, 1 Nov 2011, Jesse Barnes wrote: > > > On Tue, 1 Nov 2011 17:00:20 +0000 > > Matthew Garrett <mjg59@xxxxxxxxxxxxx> wrote: > > > > > On Tue, Nov 01, 2011 at 09:57:45AM -0700, Jesse Barnes wrote: > > > > On Tue, 1 Nov 2011 07:47:05 -0700 > > > > Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > > I think that the PCI "poll for PME" logic should just resume the > > > > > device - and *not* suspend it again. Maybe it can suspend it next time > > > > > around when it polls, if PME has been cleared. That should be (a) sane > > > > > and (b) obviate any need for some random delay in some random driver. > > > > > > > > > > Jesse? > > > > > > > > > > That said, Matthew's suggestion sounds like a good idea regardless. > > > > > > > > Yeah that makes sense. But hopefully we can get away without polling > > > > at all if we actually implement PME message interrupt support on the > > > > host bridge side. Does anyone with affected hardware want to try that? > > > > I think the publicly available docs have enough info to do it... > > > > > > Don't we already have that, assuming the hardware gives us control via > > > _OSC? The problem we've seen is that a pile of hardware appears to set > > > the PME flag without generating any interrupt, regardless of whether > > > we're in ACPI or native delivery modes. > > > > On Linus's machine, we didn't see any GPEs and neither does there seem > > to be an interrupt handler registered for the PME interrupt... Not > > that having one registered will guarnatee us anything, but it's worth > > forcing it to see if we at least get interrupts (though that assumes > > the NEC device is actually sending PME messages to the root complex > > correctly). > > > > Either way, I guess the BIOS on this machine just doesn't expect PME > > to be used on this device at all... > > Pardon me for being slow, but I don't see how this is related to the > problem Linus reported. Namely, that _every_ PM event caused both of > the EHCI controllers to be resumed, even if they had nothing to do with > the event in question. Yeah, I was going back to the original problem of why we didn't get wakeups from the NEC device. I'd like to avoid polling if at all possible... -- Jesse Barnes, Intel Open Source Technology Center
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