ACPI: processor: idle: Fix ACPI idle handling in power notify on failure

[PATCH 1/3] cpuidle: Add enable_cpuidle() interface

Posted by Huisong Li 2 months, 2 weeks ago

The global switch of cpuidle can be turned back on in some case.
So add enable_cpuidle().

Signed-off-by: Huisong Li <lihuisong@huawei.com>
---
 drivers/cpuidle/cpuidle.c | 5 ++++-
 include/linux/cpuidle.h   | 2 ++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 56132e843c99..980ddfd3d930 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -48,7 +48,10 @@ void disable_cpuidle(void)
 {
 	off = 1;
 }
-
+void enable_cpuidle(void)
+{
+	off = 0;
+}
 bool cpuidle_not_available(struct cpuidle_driver *drv,
 			   struct cpuidle_device *dev)
 {
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index a9ee4fe55dcf..94c030748af3 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -168,6 +168,7 @@ struct cpuidle_driver {
 };
 
 #ifdef CONFIG_CPU_IDLE
+extern void enable_cpuidle(void);
 extern void disable_cpuidle(void);
 extern bool cpuidle_not_available(struct cpuidle_driver *drv,
 				  struct cpuidle_device *dev);
@@ -203,6 +204,7 @@ extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev)
 static inline struct cpuidle_device *cpuidle_get_device(void)
 {return __this_cpu_read(cpuidle_devices); }
 #else
+static inline void enable_cpuidle(void) { }
 static inline void disable_cpuidle(void) { }
 static inline bool cpuidle_not_available(struct cpuidle_driver *drv,
 					 struct cpuidle_device *dev)
-- 
2.33.0

Re: [PATCH 1/3] cpuidle: Add enable_cpuidle() interface

Posted by Rafael J. Wysocki 3 weeks, 4 days ago

On Tue, Nov 25, 2025 at 8:29 AM Huisong Li <lihuisong@huawei.com> wrote:
>
> The global switch of cpuidle can be turned back on in some case.
> So add enable_cpuidle().

No, this is not going to work.  The "off" switch only affects
initialization AFAICS.

> Signed-off-by: Huisong Li <lihuisong@huawei.com>
> ---
>  drivers/cpuidle/cpuidle.c | 5 ++++-
>  include/linux/cpuidle.h   | 2 ++
>  2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
> index 56132e843c99..980ddfd3d930 100644
> --- a/drivers/cpuidle/cpuidle.c
> +++ b/drivers/cpuidle/cpuidle.c
> @@ -48,7 +48,10 @@ void disable_cpuidle(void)
>  {
>         off = 1;
>  }
> -
> +void enable_cpuidle(void)
> +{
> +       off = 0;
> +}
>  bool cpuidle_not_available(struct cpuidle_driver *drv,
>                            struct cpuidle_device *dev)
>  {
> diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
> index a9ee4fe55dcf..94c030748af3 100644
> --- a/include/linux/cpuidle.h
> +++ b/include/linux/cpuidle.h
> @@ -168,6 +168,7 @@ struct cpuidle_driver {
>  };
>
>  #ifdef CONFIG_CPU_IDLE
> +extern void enable_cpuidle(void);
>  extern void disable_cpuidle(void);
>  extern bool cpuidle_not_available(struct cpuidle_driver *drv,
>                                   struct cpuidle_device *dev);
> @@ -203,6 +204,7 @@ extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev)
>  static inline struct cpuidle_device *cpuidle_get_device(void)
>  {return __this_cpu_read(cpuidle_devices); }
>  #else
> +static inline void enable_cpuidle(void) { }
>  static inline void disable_cpuidle(void) { }
>  static inline bool cpuidle_not_available(struct cpuidle_driver *drv,
>                                          struct cpuidle_device *dev)
> --
> 2.33.0
>

Re: [PATCH 1/3] cpuidle: Add enable_cpuidle() interface

Posted by lihuisong (C) 3 weeks, 4 days ago

On 1/15/2026 3:18 AM, Rafael J. Wysocki wrote:
> On Tue, Nov 25, 2025 at 8:29 AM Huisong Li <lihuisong@huawei.com> wrote:
>> The global switch of cpuidle can be turned back on in some case.
>> So add enable_cpuidle().
> No, this is not going to work.  The "off" switch only affects
> initialization AFAICS.
I think it would be work.
The cpuidle_not_available() also see the "off" on do_idle().
And cpuidle_idle_call() check this function first and then select idle 
state.
Cpuidle doesn't select and enter idle state if this fuction return true.
>> Signed-off-by: Huisong Li <lihuisong@huawei.com>
>> ---
>>   drivers/cpuidle/cpuidle.c | 5 ++++-
>>   include/linux/cpuidle.h   | 2 ++
>>   2 files changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
>> index 56132e843c99..980ddfd3d930 100644
>> --- a/drivers/cpuidle/cpuidle.c
>> +++ b/drivers/cpuidle/cpuidle.c
>> @@ -48,7 +48,10 @@ void disable_cpuidle(void)
>>   {
>>          off = 1;
>>   }
>> -
>> +void enable_cpuidle(void)
>> +{
>> +       off = 0;
>> +}
>>   bool cpuidle_not_available(struct cpuidle_driver *drv,
>>                             struct cpuidle_device *dev)
>>   {
>> diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
>> index a9ee4fe55dcf..94c030748af3 100644
>> --- a/include/linux/cpuidle.h
>> +++ b/include/linux/cpuidle.h
>> @@ -168,6 +168,7 @@ struct cpuidle_driver {
>>   };
>>
>>   #ifdef CONFIG_CPU_IDLE
>> +extern void enable_cpuidle(void);
>>   extern void disable_cpuidle(void);
>>   extern bool cpuidle_not_available(struct cpuidle_driver *drv,
>>                                    struct cpuidle_device *dev);
>> @@ -203,6 +204,7 @@ extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev)
>>   static inline struct cpuidle_device *cpuidle_get_device(void)
>>   {return __this_cpu_read(cpuidle_devices); }
>>   #else
>> +static inline void enable_cpuidle(void) { }
>>   static inline void disable_cpuidle(void) { }
>>   static inline bool cpuidle_not_available(struct cpuidle_driver *drv,
>>                                           struct cpuidle_device *dev)
>> --
>> 2.33.0
>>

Re: [PATCH 1/3] cpuidle: Add enable_cpuidle() interface

Posted by lihuisong (C) 1 week, 3 days ago

Hi Rafael,

On 1/15/2026 8:18 PM, lihuisong (C) wrote:
>
> On 1/15/2026 3:18 AM, Rafael J. Wysocki wrote:
>> On Tue, Nov 25, 2025 at 8:29 AM Huisong Li <lihuisong@huawei.com> wrote:
>>> The global switch of cpuidle can be turned back on in some case.
>>> So add enable_cpuidle().
>> No, this is not going to work.  The "off" switch only affects
>> initialization AFAICS.
> I think it would be work.
> The cpuidle_not_available() also see the "off" on do_idle().
> And cpuidle_idle_call() check this function first and then select idle 
> state.
> Cpuidle doesn't select and enter idle state if this fuction return true.
I verified that disable_cpuidle() effectively prevents all CPUs from 
entering any idle states and the cpuidle function is correctly restored 
after calling enable_cpuidle().
What do you think?

Best,
/Huisong
>>> Signed-off-by: Huisong Li <lihuisong@huawei.com>
>>> ---
>>>   drivers/cpuidle/cpuidle.c | 5 ++++-
>>>   include/linux/cpuidle.h   | 2 ++
>>>   2 files changed, 6 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
>>> index 56132e843c99..980ddfd3d930 100644
>>> --- a/drivers/cpuidle/cpuidle.c
>>> +++ b/drivers/cpuidle/cpuidle.c
>>> @@ -48,7 +48,10 @@ void disable_cpuidle(void)
>>>   {
>>>          off = 1;
>>>   }
>>> -
>>> +void enable_cpuidle(void)
>>> +{
>>> +       off = 0;
>>> +}
>>>   bool cpuidle_not_available(struct cpuidle_driver *drv,
>>>                             struct cpuidle_device *dev)
>>>   {
>>> diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
>>> index a9ee4fe55dcf..94c030748af3 100644
>>> --- a/include/linux/cpuidle.h
>>> +++ b/include/linux/cpuidle.h
>>> @@ -168,6 +168,7 @@ struct cpuidle_driver {
>>>   };
>>>
>>>   #ifdef CONFIG_CPU_IDLE
>>> +extern void enable_cpuidle(void);
>>>   extern void disable_cpuidle(void);
>>>   extern bool cpuidle_not_available(struct cpuidle_driver *drv,
>>>                                    struct cpuidle_device *dev);
>>> @@ -203,6 +204,7 @@ extern struct cpuidle_driver 
>>> *cpuidle_get_cpu_driver(struct cpuidle_device *dev)
>>>   static inline struct cpuidle_device *cpuidle_get_device(void)
>>>   {return __this_cpu_read(cpuidle_devices); }
>>>   #else
>>> +static inline void enable_cpuidle(void) { }
>>>   static inline void disable_cpuidle(void) { }
>>>   static inline bool cpuidle_not_available(struct cpuidle_driver *drv,
>>>                                           struct cpuidle_device *dev)
>>> -- 
>>> 2.33.0
>>>