Fix panic on boot for latest Macbooks
 

Some, if not all, of the latest round of Macbooks panic on boot with the
message "timer doesn't work through interrupt-remapped IO-APIC". This is
triggered by a bug in the ACPI tables that makes the kernel unable to
find the matching interrupt remapping unit for the IOAPIC, causing
interrupt remapping to fail and ultimately leading to this panic.

The following patch to fix this issue is currently staged in the
upstream iommu/fixes branch for 3.6. This issue affects other releases
besides quantal (I've verified precise is affected, and other stable
kernels are likely affected as well). However, I'm recommending we let
this bake in the development kernel for a little while before applying
it to any stable releases.

Thanks,
Seth


Seth Forshee (1):
UBUNTU: SAUCE: (drop after 3.6) irq_remap: disable IRQ remapping if
any IOAPIC lacks an IOMMU

drivers/iommu/intel_irq_remapping.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)


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