diff options
authorLen Brown <>2009-05-15 01:29:31 -0400
committerLen Brown <>2009-05-16 01:52:39 -0400
commita0bf284bfedd6dc95bbee7ebf5ccf3b5f753a008 (patch)
parent520daf7217bc1806c02eb4cfa7805447a3da2f66 (diff)
ACPI: Idle C-states disabled by max_cstate should not disable the TSC
Processor idle power states C2 and C3 stop the TSC on many machines. Linux recognizes this situation and marks the TSC as unstable: Marking TSC unstable due to TSC halts in idle But if those same machines are booted with "processor.max_cstate=1", then there is no need to validate C2 and C3, and no need to disable the TSC, which can be reliably used as a clocksource. Signed-off-by: Len Brown <> Acked-by: Thomas Gleixner <>
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index e39a40a2ceae..e65476fdf40d 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -582,7 +582,7 @@ static int acpi_processor_power_verify(struct acpi_processor *pr)
pr->power.timer_broadcast_on_state = INT_MAX;
- for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
+ for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
struct acpi_processor_cx *cx = &pr->power.states[i];
switch (cx->type) {