On Wed, 8 Aug 2007, Vivek Goyal wrote: > On Tue, Aug 07, 2007 at 07:41:30PM +0200, Martin Wilck wrote: > > > > Can you explain how, on the front side bus, the IO-APIC knows whether > > a CPU has accepted the INT message? There is no response > > to the INT message on the bus, except for the EOI which comes much later. > > I'm not saying that you're wrong, I just really don't understand this > > point. > > > > I don't know what is exactly hardware protocol. I am just going by > intel documentation.
I think it's important to distinguish between the LAPIC receiving an interrupt and the CPU receiving an interrupt. The former could happen without the latter if the CPU has set the TPR above the priority of the interrupt received by the LAPIC. In that case, the interrupt is kept pending in the LAPIC and recorded in the IRR if I understand the Intel documentation correctly. So I think the scenario which leaves IRR set when the kdump kernel starts is possible. Chip -- Charles M. "Chip" Coldwell Senior Software Engineer Red Hat, Inc 978-392-2426 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
