Re: 2.6.29: can't resume from suspend with DMAR (intel iommu)enabled

From: David Woodhouse
Date: Wed Mar 25 2009 - 14:05:06 EST


On Wed, 2009-03-25 at 18:59 +0100, Ingo Molnar wrote:
>
> that's not easy - i use it right now :)
>
> That's another reason why warnings and non-panic() behavior are
> better for developers too. Had it not crashed i could have sent you
> my dmesg and i would not have turned off DMAR in the BIOS.
>
> Now it's turned off in my BIOS (first barrier) and i need to reboot
> the kernel (second barrier) and i need to hack up a kernel in a
> certain way to produce debug info (third barrier) - in the merge
> window (fourth barrier ;-).

Yeah, trusting BIOS monkeys for this was always going to be a bad plan.
We should have just known how to set/read the damn hardware BARs -- the
most likely explanation for this is that your BIOS is just lying to you
about where it put the registers, I believe.

I'd like to put in a basic sanity check when we first ioremap the
(alleged) DMAR registers. Hopefully, the output I asked for will confirm
that there's a simple way to do that...

--
David Woodhouse Open Source Technology Centre
David.Woodhouse@xxxxxxxxx Intel Corporation

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