From: Dave Hansen <haveblue@us.ibm.com>
Date: Fri, 29 Jul 2005 04:16:18 +0000 (-0700)
Subject: [PATCH] re-disable TSC on NUMAQ
X-Git-Tag: v2.6.13-rc5~112
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e1474e2d9dfb782e6c6517a180b5a8913c69dfad;p=linux-2.6

[PATCH] re-disable TSC on NUMAQ

Somewhere recently, the TSC got re-enabled for timekeeping on NUMAQ
machines.  However, the hardware makes these get unsynchronized quite
badly.  So badly, in fact, that the code to fix up the skew can just hang
on boot.

This patch re-disables them.  It's nicely confined to the numaq.c file.  It
would be great if this could make it into 2.6.13, I think it counts as a
bugfix.

Tested on a 16-proc 4-node NUMAQ.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/arch/i386/kernel/numaq.c b/arch/i386/kernel/numaq.c
index e51edf0a65..5f5b075f86 100644
--- a/arch/i386/kernel/numaq.c
+++ b/arch/i386/kernel/numaq.c
@@ -31,6 +31,7 @@
 #include <linux/nodemask.h>
 #include <asm/numaq.h>
 #include <asm/topology.h>
+#include <asm/processor.h>
 
 #define	MB_TO_PAGES(addr) ((addr) << (20 - PAGE_SHIFT))
 
@@ -77,3 +78,11 @@ int __init get_memcfg_numaq(void)
 	smp_dump_qct();
 	return 1;
 }
+
+static int __init numaq_dsc_disable(void)
+{
+	printk(KERN_DEBUG "NUMAQ: disabling TSC\n");
+	tsc_disable = 1;
+	return 0;
+}
+core_initcall(numaq_dsc_disable);