Messages in this thread | | | Date | Tue, 9 Jul 2013 16:43:31 -0700 | From | Guenter Roeck <> | Subject | Re: WARNING: at drivers/iommu/dmar.c:484 warn_invalid_dmar with Intel Motherboard |
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On Tue, Jul 09, 2013 at 04:22:52PM -0700, Chris Wright wrote: > * Guenter Roeck (linux@roeck-us.net) wrote: > > On Tue, Jul 09, 2013 at 03:05:39PM -0600, Bjorn Helgaas wrote: > > > [+cc Joerg, David, iommu list] > > > > > > On Tue, Jul 9, 2013 at 2:24 PM, Guenter Roeck <linux@roeck-us.net> wrote: > > > > I started seeing this problem after updating the BIOS trying fix another issue, > > > > though I may have missed it earlier. > > > > > > > > I understand this is a BIOS bug. Would be great if someone can pass this on > > > > to Intel BIOS engineers. > > > > > > Maybe. It'd be nice if Linux handled it better, though. > > > > > If anyone has an idea how to do that, I'll be happy to write a patch. > > I'm not sure there's much you can do. The BIOS is saying there's a DMAR > unit, and then saying the registers are at addr 0x0. The kernel is > simply warning you about the invalid DMAR table entry. > > One thing I've seen is the BIOS zeroing the base register address when > VT-d is disabled in BIOS. So, Guenter, a "fix" may be simply enabling > VT-d in the BIOS. > Ah, yes, I think I may have that disabled. I'll check it tonight.
Does that really warrant a traceback, or would a warning message be more appropriate (possibly telling the user to enable VT-d) ?
Thanks, Guenter
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