Messages in this thread | | | Date | Thu, 11 Oct 2012 11:32:39 +0200 | From | Joerg Roedel <> | Subject | Re: [git pull] IOMMU Updates for v3.7-rc1 |
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On Wed, Oct 10, 2012 at 11:02:31PM +0100, Andrew Oakley wrote: > On Wed, 10 Oct 2012 20:11:31 +0100 > Andrew Oakley <andrew@ado.is-a-geek.net> wrote:
> I'm not sure if the fix I've got is safe or if it's really a good idea > to enable interrupt remapping with a broken BIOS.
Sadly it is not. Your patch works for your particular case but is not generally applicable. There are indeed systems with 2 or more IOAPICs and they all use different device-ids.
So, typically, there is one IOAPIC per SB, like in your case. But on RD890 the chipset NB also includes an IOAPIC (which uses device-id 00:00.1). This IOAPIC exists on your system too but is disabled by the BIOS because the board does not use it.
So, in the end, device-id 00:00.1 might also be correct and the IVRS entry could refer to the NB IOAPIC. We don't have any reliable indication which IOAPIC is described in the IVRS table.
Cheer,
Joerg
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