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SubjectRe: [linux-pm] [PATCH 08/18] cpuidle: create bootparam "cpuidle.off=1"

On Saturday 02 April 2011 11:52 AM, Len Brown wrote:
> From: Len Brown <len.brown@intel.com>
>
> 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: Len Brown <len.brown@intel.com>
> ---
> Documentation/kernel-parameters.txt | 3 +++
> drivers/cpuidle/cpuidle.c | 10 ++++++++++
> drivers/cpuidle/cpuidle.h | 1 +
> drivers/cpuidle/driver.c | 3 +++
> drivers/cpuidle/governor.c | 3 +++
> 5 files changed, 20 insertions(+), 0 deletions(-)
>
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index f4a04c0..08e8a22 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -546,6 +546,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
> /proc/<pid>/coredump_filter.
> 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
> Format:
> <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
> index bf50924..faae2c3 100644
> --- a/drivers/cpuidle/cpuidle.c
> +++ b/drivers/cpuidle/cpuidle.c
> @@ -28,6 +28,12 @@ LIST_HEAD(cpuidle_detected_devices);
> static void (*pm_idle_old)(void);
>
> static int enabled_devices;
> +static int off __read_mostly;
> +
> +int cpuidle_disabled(void)
> +{
> + return off;
> +}
>
> #if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT)
> static void cpuidle_kick_cpus(void)
> @@ -427,6 +433,9 @@ static int __init cpuidle_init(void)
> {
> int ret;
>
> + if (cpuidle_disabled())
> + return -ENODEV;
> +
> pm_idle_old = pm_idle;
>
> ret = cpuidle_add_class_sysfs(&cpu_sysdev_class);
> @@ -438,4 +447,5 @@ static int __init cpuidle_init(void)
> return 0;
> }
>
> +module_param(off, int, 0444);
> core_initcall(cpuidle_init);
> diff --git a/drivers/cpuidle/cpuidle.h b/drivers/cpuidle/cpuidle.h
> index 33e50d5..38c3fd8 100644
> --- a/drivers/cpuidle/cpuidle.h
> +++ b/drivers/cpuidle/cpuidle.h
> @@ -13,6 +13,7 @@ extern struct list_head cpuidle_governors;
> extern struct list_head cpuidle_detected_devices;
> extern struct mutex cpuidle_lock;
> extern spinlock_t cpuidle_driver_lock;
> +extern int cpuidle_disabled(void);
>
> /* idle loop */
> extern void cpuidle_install_idle_handler(void);
> diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
> index fd1601e..3f7e3ce 100644
> --- a/drivers/cpuidle/driver.c
> +++ b/drivers/cpuidle/driver.c
> @@ -26,6 +26,9 @@ int cpuidle_register_driver(struct cpuidle_driver *drv)
> if (!drv)
> return -EINVAL;
>
> + if (cpuidle_disabled())
> + return -ENODEV;
> +
> spin_lock(&cpuidle_driver_lock);
> if (cpuidle_curr_driver) {
> spin_unlock(&cpuidle_driver_lock);
> diff --git a/drivers/cpuidle/governor.c b/drivers/cpuidle/governor.c
> index 724c164..ea2f8e7 100644
> --- a/drivers/cpuidle/governor.c
> +++ b/drivers/cpuidle/governor.c
> @@ -81,6 +81,9 @@ int cpuidle_register_governor(struct cpuidle_governor *gov)
> if (!gov || !gov->select)
> return -EINVAL;
>
> + if (cpuidle_disabled())
> + return -ENODEV;
> +
> mutex_lock(&cpuidle_lock);
> if (__cpuidle_find_governor(gov->name) == NULL) {
> ret = 0;

Hi Len,
We would like to know as to when the patch that completely removes
pm_idle for x86 "cpuidle: stop using pm_idle" and that which introduces
bootparam cpuidle.off "cpuidle: create bootparam cpuidle.off=1"
be pushed ? Are there any dependencies that needs to be addressed
before queuing it up for the next merge window ? If yes, can you please
let us know what the dependencies are. We need these patches for running
cpuidle driver for pseries.
https://lkml.org/lkml/2011/6/7/375

Thanks
- Deepthi








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