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

[lihuisong (C)]

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@xxxxxxxxxx> 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@xxxxxxxxxx>
> > > ---
> > >   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