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Commit 62027aea authored by Len Brown's avatar Len Brown
Browse files

cpuidle: create bootparam "cpuidle.off=1" 



useful for disabling cpuidle to fall back
to architecture-default idle loop

cpuidle drivers and governors will fail to register.
on x86 they'll say so:

intel_idle: intel_idle yielding to (null)
ACPI: acpi_idle yielding to (null)

Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent 6dccf9c5

Documentation/kernel-parameters.txt

+3 −0
Original line number Original line Diff line number Diff line
@@ -546,6 +546,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 
			/proc/<pid>/coredump_filter.

			/proc/<pid>/coredump_filter.

			See also Documentation/filesystems/proc.txt.

			See also Documentation/filesystems/proc.txt.





	cpuidle.off=1	[CPU_IDLE]

			disable the cpuidle sub-system



	cpcihp_generic=	[HW,PCI] Generic port I/O CompactPCI driver

	cpcihp_generic=	[HW,PCI] Generic port I/O CompactPCI driver

			Format:

			Format:

			<first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]

			<first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]

drivers/cpuidle/cpuidle.c

+10 −0
Original line number Original line Diff line number Diff line
@@ -28,6 +28,12 @@ LIST_HEAD(cpuidle_detected_devices); 
static void (*pm_idle_old)(void);

static void (*pm_idle_old)(void);





static int enabled_devices;

static int enabled_devices;

static int off __read_mostly;



int cpuidle_disabled(void)

{

	return off;

}





#if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT)

#if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT)

static void cpuidle_kick_cpus(void)

static void cpuidle_kick_cpus(void)
@@ -427,6 +433,9 @@ static int __init cpuidle_init(void) 
{

{

	int ret;

	int ret;





	if (cpuidle_disabled())

		return -ENODEV;



	pm_idle_old = pm_idle;

	pm_idle_old = pm_idle;





	ret = cpuidle_add_class_sysfs(&cpu_sysdev_class);

	ret = cpuidle_add_class_sysfs(&cpu_sysdev_class);
@@ -438,4 +447,5 @@ static int __init cpuidle_init(void) 
	return 0;

	return 0;

}

}





module_param(off, int, 0444);

core_initcall(cpuidle_init);
 
core_initcall(cpuidle_init);

drivers/cpuidle/cpuidle.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -13,6 +13,7 @@ extern struct list_head cpuidle_governors; 
extern struct list_head cpuidle_detected_devices;

extern struct list_head cpuidle_detected_devices;

extern struct mutex cpuidle_lock;

extern struct mutex cpuidle_lock;

extern spinlock_t cpuidle_driver_lock;

extern spinlock_t cpuidle_driver_lock;

extern int cpuidle_disabled(void);





/* idle loop */

/* idle loop */

extern void cpuidle_install_idle_handler(void);

extern void cpuidle_install_idle_handler(void);

drivers/cpuidle/driver.c

+3 −0
Original line number Original line Diff line number Diff line
@@ -26,6 +26,9 @@ int cpuidle_register_driver(struct cpuidle_driver *drv) 
	if (!drv)

	if (!drv)

		return -EINVAL;

		return -EINVAL;





	if (cpuidle_disabled())

		return -ENODEV;



	spin_lock(&cpuidle_driver_lock);

	spin_lock(&cpuidle_driver_lock);

	if (cpuidle_curr_driver) {

	if (cpuidle_curr_driver) {

		spin_unlock(&cpuidle_driver_lock);

		spin_unlock(&cpuidle_driver_lock);

drivers/cpuidle/governor.c

+3 −0
Original line number Original line Diff line number Diff line
@@ -81,6 +81,9 @@ int cpuidle_register_governor(struct cpuidle_governor *gov) 
	if (!gov || !gov->select)

	if (!gov || !gov->select)

		return -EINVAL;

		return -EINVAL;





	if (cpuidle_disabled())

		return -ENODEV;



	mutex_lock(&cpuidle_lock);

	mutex_lock(&cpuidle_lock);

	if (__cpuidle_find_governor(gov->name) == NULL) {

	if (__cpuidle_find_governor(gov->name) == NULL) {

		ret = 0;

		ret = 0;