Re: [5/6] 2.6.21-rc2: known regressions

[Ingo Molnar]

* Daniel Walker <dwalker@xxxxxxxxxx> wrote:

> > > FYI, this is not a "wont boot" problem, this should be a "NMI 
> > > watchdog does not work" problem - which has far lower severity. 
> > > Also, Thomas did a fix for this which is now in -mm.
> > 
> > yup, you should be able to cross this one off, Adrian.  The fix 
> > worked for me, at least.
> 
> I didn't see a fix for this one go by .. I'll check the usual places I 
> guess ..

find it below.

	Ingo

------------------------------------------------------
Subject: fix "NMI appears to be stuck"
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

  Testing NMI watchdog ... CPU#0: NMI appears to be stuck (54->54)!
  CPU#1: NMI appears to be stuck (0->0)!

Keep the PIT/HPET alive when nmi_watchdog = 1 is given on the command
line.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 arch/i386/kernel/apic.c |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diff -puN arch/i386/kernel/apic.c~fix-nmi-appears-to-be-stuck arch/i386/kernel/apic.c
--- a/arch/i386/kernel/apic.c~fix-nmi-appears-to-be-stuck
+++ a/arch/i386/kernel/apic.c
@@ -493,8 +493,15 @@ void __init setup_boot_APIC_clock(void)
 		/* No broadcast on UP ! */
 		if (num_possible_cpus() == 1)
 			return;
-	} else
-		lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
+	} else {
+		/*
+		 * If nmi_watchdog is set to IO_APIC, we need the
+		 * PIT/HPET going. So we register lapic as a dummy
+		 * device.
+		 */
+		if (nmi_watchdog != NMI_IO_APIC)
+			lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
+	}
 
 	/* Setup the lapic or request the broadcast */
 	setup_APIC_timer();
-
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