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authorThomas Gleixner <tglx@linutronix.de>2007-03-23 11:08:01 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-03-23 13:21:02 -0400
commite585bef815c0315f2730d7bb4e15b82602454efd (patch)
tree914d777ba187e656a89075398f81e485885f0aab /arch
parent296d93cd0205433489b0689533426ce0a8cf2dec (diff)
[PATCH] i386: add command line option "local_apic_timer_c2_ok"
It turned out that it is almost impossible to trust ACPI, BIOS & Co. regarding the C states. This was the reason to switch the local apic timer off in C2 state already. OTOH there are sane and well behaving systems, which get punished by that decision. Allow the user to confirm that the local apic timer is trustworthy in C2 state. This keeps the default behaviour on the safe side. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/i386/kernel/apic.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
index 244c3fe9b8c3..e88415282a6f 100644
--- a/arch/i386/kernel/apic.c
+++ b/arch/i386/kernel/apic.c
@@ -64,6 +64,9 @@ static int enable_local_apic __initdata = 0;
64static int local_apic_timer_verify_ok; 64static int local_apic_timer_verify_ok;
65/* Disable local APIC timer from the kernel commandline or via dmi quirk */ 65/* Disable local APIC timer from the kernel commandline or via dmi quirk */
66static int local_apic_timer_disabled; 66static int local_apic_timer_disabled;
67/* Local APIC timer works in C2 */
68int local_apic_timer_c2_ok;
69EXPORT_SYMBOL_GPL(local_apic_timer_c2_ok);
67 70
68/* 71/*
69 * Debug level, exported for io_apic.c 72 * Debug level, exported for io_apic.c
@@ -1232,6 +1235,13 @@ static int __init parse_disable_lapic_timer(char *arg)
1232} 1235}
1233early_param("nolapic_timer", parse_disable_lapic_timer); 1236early_param("nolapic_timer", parse_disable_lapic_timer);
1234 1237
1238static int __init parse_lapic_timer_c2_ok(char *arg)
1239{
1240 local_apic_timer_c2_ok = 1;
1241 return 0;
1242}
1243early_param("lapic_timer_c2_ok", parse_lapic_timer_c2_ok);
1244
1235static int __init apic_set_verbosity(char *str) 1245static int __init apic_set_verbosity(char *str)
1236{ 1246{
1237 if (strcmp("debug", str) == 0) 1247 if (strcmp("debug", str) == 0)