[RFC,v2,9/9] intel_idle: Add module parameter to prevent ACPI _CST from being used
diff mbox series

Message ID 2442105.UMyhRX9LH8@kreacher
State New
Headers show
  • cpuidle: intel_idle: Use ACPI _CTS to get idle states information
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Commit Message

Rafael J. Wysocki Dec. 10, 2019, 12:13 p.m. UTC
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Add a new module parameter called "no_acpi" to the intel_idle driver
to allow the driver to be prevented from using ACPI _CST via kernel
command line.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 drivers/idle/intel_idle.c |    9 +++++++++
 1 file changed, 9 insertions(+)

diff mbox series

Index: linux-pm/drivers/idle/intel_idle.c
--- linux-pm.orig/drivers/idle/intel_idle.c
+++ linux-pm/drivers/idle/intel_idle.c
@@ -1138,6 +1138,10 @@  static bool intel_idle_max_cstate_reache
 #include <acpi/processor.h>
+static bool no_acpi __read_mostly;
+module_param(no_acpi, bool, 0444);
+MODULE_PARM_DESC(no_acpi, "Do not use ACPI _CST for building the idle states list");
 static struct acpi_processor_power acpi_state_table;
@@ -1167,6 +1171,11 @@  static bool intel_idle_acpi_cst_extract(
 	unsigned int cpu;
+	if (no_acpi) {
+		pr_debug("Not allowed to use ACPI _CST\n");
+		return false;
+	}
 	for_each_possible_cpu(cpu) {
 		struct acpi_processor *pr = per_cpu(processors, cpu);