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

[Ingo Molnar <mingo@elte.hu>]

* David Woodhouse <dwmw2@infradead.org> wrote:

> 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...

Could you please fix the panic() and add the debug output you'd like 
to see? That would give me a kernel to run straight away. Without me 
having to think much about what i should run and when.

(unless you really need this pr_debug info to proceed)

But it will be some time really. The laptop has 8 days uptime and is 
not set up to run custom kernels at all.

	Ingo