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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Fri, 25 Sep 2020 16:41:56 +0200
Message-ID: <CAJZ5v0ipTw3nwcWp2yYQ7SEpp0jeC8gQRK4nr8T95_UuXmP+HQ@mail.gmail.com>
Subject: Re: [PATCH] cpuidle: change #ifdef for the declaration of cpuidle_enter_s2idle()
To:     zhuguangqing83@gmail.com
Cc:     "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Linux PM <linux-pm@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        zhuguangqing <zhuguangqing@xiaomi.com>
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On Thu, Sep 24, 2020 at 10:01 AM <zhuguangqing83@gmail.com> wrote:
>
> From: zhuguangqing <zhuguangqing@xiaomi.com>
>
> Currently, if CONFIG_SUSPEND=n and CONFIG_CPU_IDLE=y, the function
> cpuidle_enter_s2idle() is declared but not defined, it may cause error
> when cpuidle_enter_s2idle() is called.
>
> If CONFIG_SUSPEND=y and CONFIG_CPU_IDLE=n, the function
> cpuidle_enter_s2idle() is defined as "return -ENODEV;" which is not
> supposed to be.
>
> Change #ifdef CONFIG_CPU_IDLE to #ifdef CONFIG_SUSPEND for
> cpuidle_enter_s2idle() in cpuidle.h, which is consistent with its
> defination in cpuidle.c.

Well, what about the case when CONFIG_SUSPEND is set, but CONFIG_CPU_IDLE isn't?

>
> Signed-off-by: zhuguangqing <zhuguangqing@xiaomi.com>
> ---
>  include/linux/cpuidle.h | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
> index 6175c77bf25e..2aa8cead1727 100644
> --- a/include/linux/cpuidle.h
> +++ b/include/linux/cpuidle.h
> @@ -216,22 +216,26 @@ static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; }
>  extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
>                                       struct cpuidle_device *dev,
>                                       u64 latency_limit_ns);
> -extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
> -                               struct cpuidle_device *dev);
>  extern void cpuidle_use_deepest_state(u64 latency_limit_ns);
>  #else
>  static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
>                                              struct cpuidle_device *dev,
>                                              u64 latency_limit_ns)
>  {return -ENODEV; }
> -static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
> -                                      struct cpuidle_device *dev)
> -{return -ENODEV; }
>  static inline void cpuidle_use_deepest_state(u64 latency_limit_ns)
>  {
>  }
>  #endif
>
> +#ifdef CONFIG_SUSPEND
> +extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
> +                               struct cpuidle_device *dev);
> +#else
> +static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
> +                                      struct cpuidle_device *dev)
> +{return -ENODEV; }
> +#endif
> +
>  /* kernel/sched/idle.c */
>  extern void sched_idle_set_state(struct cpuidle_state *idle_state);
>  extern void default_idle_call(void);
> --
> 2.17.1
>