From a0bf284bfedd6dc95bbee7ebf5ccf3b5f753a008 Mon Sep 17 00:00:00 2001 From: Len Brown Date: Fri, 15 May 2009 01:29:31 -0400 Subject: [PATCH] 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 --- drivers/acpi/processor_idle.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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) { -- 2.30.2