Re: IRQ remapping problem on Macbook Air 5,1

[Suresh Siddha]

On Tue, 2012-08-07 at 15:55 -0500, Seth Forshee wrote:
> On Tue, Aug 07, 2012 at 01:47:52PM -0700, Suresh Siddha wrote:
> > On Tue, 2012-08-07 at 22:10 +0200, Joerg Roedel wrote:
> > > 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.
> > 
> > This issue should be caught by the current check in
> > parse_ioapics_under_ir()
> > 
> > if (ir_supported && ir_ioapic_num != nr_ioapics) {
> > ...
> 
> No, there's one IOMMU and one IOAPIC, so this check doesn't catch it.
> The problem is that the ids in the ACPI tables for the devices don't
> match.
> 

Seth, I am referring to the issue that Joerg raised. Not referring to
your current issue.

thanks,
suresh

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/