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SubjectRe: [PATCH] NMI watchdog documentation
On Tue, 29 Jul 2003 18:06:30 +0200, Andi Kleen wrote:
>Right, 1 and 2 need to be exchanged. Anyways local apic mode does not seem
>to work, the kernel always reportss "NMI stuck" at bootup.
>IO APIC mode for is default.

That's strange. I've tested perfctr-generated interrupts through
the local APIC on Opteron, and they work with the perfctr driver.

Two things you might want to test:
- In case the unofficial event 0x76 really doesn't work in your
version of the chip, try this event specifier instead: it
creates a clock-like event using an inverted threshold approach.
I've tested this on K8 and P6 with the perfctr driver. The event
code (0xC0) is immaterial, 0x00 and 0xFF work equally well.

--- linux-2.6.0-test2/arch/x86_64/kernel/nmi.c.~1~ 2003-07-03 12:32:44.000000000 +0200
+++ linux-2.6.0-test2/arch/x86_64/kernel/nmi.c 2003-07-30 20:46:21.412657728 +0200
@@ -51,7 +51,7 @@
#define K7_EVNTSEL_OS (1 << 17)
#define K7_EVNTSEL_USR (1 << 16)
+#define K7_NMI_EVENT (0xC0 | (1<<23) | (0xFF << 24))

#define P6_EVNTSEL0_ENABLE (1 << 22)
#define P6_EVNTSEL_INT (1 << 20)
- My perfctr driver routes interrupts through LVTPC programmed for
Fixed delivery mode. Maybe the NMI delivery mode is broken. You
could try changing the NMI watchdog to use a new vector and Fixed
delivery mode, just to see if the watchdog starts ticking.

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