linux-kernel - [PATCH] Revert nmi_known_cpu() check during boot option parsing

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Date:	Wed, 10 Jan 2007 15:05:10 -0800
From:	Venkatesh Pallipadi <venkatesh.pallipadi@...el.com>
To:	Andrew Morton <akpm@...l.org>
Cc:	Andi Kleen <ak@...e.de>, dzickus@...hat.com,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: [PATCH] Revert nmi_known_cpu() check during boot option parsing


The patch 
http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=f2802e7f571c05f9a901b1f5bd144aa730ccc88e
and another subsequent patch adds nmi_known_cpu() check while parsing boot
options in x86_64 and i386. With that, "nmi_watchdog=2" stops working for me
on Intel Core 2 CPU based system.

The problem is, setup_nmi_watchdog is called while parsing the boot option
and identify_cpu is not done yet. So, the return value of nmi_known_cpu()
is not valid at this point.

Revert that check. Should not have any adverse effect as nmi_known_cpu() check
is done again later in enable_lapic_nmi_watchdog().

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@...el.com>

Index: linux-2.6.20-rc-mm/arch/i386/kernel/nmi.c
===================================================================
--- linux-2.6.20-rc-mm.orig/arch/i386/kernel/nmi.c
+++ linux-2.6.20-rc-mm/arch/i386/kernel/nmi.c
@@ -325,13 +325,7 @@ static int __init setup_nmi_watchdog(cha
 
 	if ((nmi >= NMI_INVALID) || (nmi < NMI_NONE))
 		return 0;
-	/*
-	 * If any other x86 CPU has a local APIC, then
-	 * please test the NMI stuff there and send me the
-	 * missing bits. Right now Intel P6/P4 and AMD K7 only.
-	 */
-	if ((nmi == NMI_LOCAL_APIC) && (nmi_known_cpu() == 0))
-		return 0;  /* no lapic support */
+
 	nmi_watchdog = nmi;
 	return 1;
 }
Index: linux-2.6.20-rc-mm/arch/x86_64/kernel/nmi.c
===================================================================
--- linux-2.6.20-rc-mm.orig/arch/x86_64/kernel/nmi.c
+++ linux-2.6.20-rc-mm/arch/x86_64/kernel/nmi.c
@@ -310,8 +310,6 @@ int __init setup_nmi_watchdog(char *str)
 	if ((nmi >= NMI_INVALID) || (nmi < NMI_NONE))
 		return 0;
 
-	if ((nmi == NMI_LOCAL_APIC) && (nmi_known_cpu() == 0))
-		return 0;  /* no lapic support */
 	nmi_watchdog = nmi;
 	return 1;
 }
-
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