Messages in this thread | | | Date | Tue, 7 Aug 2012 22:10:30 +0200 | From | Joerg Roedel <> | Subject | Re: IRQ remapping problem on Macbook Air 5,1 |
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Hi Seth,
On Tue, Aug 07, 2012 at 02:48:37PM -0500, Seth Forshee wrote: > This machine has a bug in its ACPI tables that's causing it to fail to > boot unless intremap=off is passed to the kernel. The MADT defines a > single IOAPIC with id 2, but the remapping unit defined in DMAR matches > id 0. Thus interrupt remapping fails, and the kernel panics with the > message "timer doesn't work through Interrupt-remapped IO-APIC." If I > force the use of the non-matching ir hardware for the IOAPIC everything > seems to works fine. dmesg for the working boot is below.
There are AMD systems with similar problems. For example I had a system with 2 IO-APICs but only one was described in the IOMMU ACPI table.
> I'm looking at how to make this machine able to boot by default. OS X > obviously boots, and Windows presumably boots as well since Apple > officially supports running Windows on its hardware.
These operating systems probably don't support interrupt remapping, or the IOMMU at all.
> I've got a patch to leave IRQ remapping disabled whenever any IOAPIC > does not have a matching ir hardware unit. This gets it to boot, but I > thought I'd check and see whether anyone had any better ideas for how to > fix this.
This is exactly how I fixed this issue on the AMD side too. Mind to submit the patch?
Thanks,
Joerg
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