Re: [patch 00/26] x64, x2apic/intr-remap: Interrupt-remapping and x2apic support

From: Suresh Siddha
Date: Sat Jul 12 2008 - 21:00:22 EST


On Fri, Jul 11, 2008 at 11:17:02PM -0700, Yinghai Lu wrote:
> also read the x2APIC spec pdf, it doesn't say anything about interrupt
> remapping...need to be used with x2apic...

We are updating the spec with more clarifications. But in short,
intr-remapping needs to be enabled prior to enabling x2apic in the CPU.

physical mode might work for < 255 id's for some. But it is HW
implementation specific and might not work from generation to generation.
chipsets or cpu's may drop the interrupts if cpu and chipset are
in different modes (one in legacy mode and another in extended).

So Intel is recommending to enable Intr-remapping before enabling x2apic.

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/