linux-kernel - Re: [PATCH] cpufreq: update 'cpufreq_suspended' after stopping governors

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Message-ID: <4306677.HsSlidkNXd@vostro.rjw.lan>
Date:	Tue, 30 Sep 2014 22:19:14 +0200
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Viresh Kumar <viresh.kumar@...aro.org>
Cc:	tianyu.lan@...el.com, linaro-kernel@...ts.linaro.org,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	"3.15+" <stable@...r.kernel.org>
Subject: Re: [PATCH] cpufreq: update 'cpufreq_suspended' after stopping governors

On Tuesday, September 30, 2014 09:33:17 AM Viresh Kumar wrote:
> Commit 8e30444e1530 ("cpufreq: fix cpufreq suspend/resume for intel_pstate")
> introduced a bug where the governors wouldn't be stopped anymore for
> ->target{_index}() drivers during suspend. This happens because
> 'cpufreq_suspended' is updated before stopping the governors during suspend and
> due to this __cpufreq_governor() would return early due to this check:
> 
> 	/* Don't start any governor operations if we are entering suspend */
> 	if (cpufreq_suspended)
> 		return 0;
> 
> This patch tries to fix this bug.
> 
> Fixes: 8e30444e1530 ("cpufreq: fix cpufreq suspend/resume for intel_pstate")
> Cc: 3.15+ <stable@...r.kernel.org> # 3.15+
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>

Queued up for 3.17, thanks!

> ---
>  drivers/cpufreq/cpufreq.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 6e93e7f..61190f6 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1658,10 +1658,8 @@ void cpufreq_suspend(void)
>  	if (!cpufreq_driver)
>  		return;
>  
> -	cpufreq_suspended = true;
> -
>  	if (!has_target())
> -		return;
> +		goto suspend;
>  
>  	pr_debug("%s: Suspending Governors\n", __func__);
>  
> @@ -1674,6 +1672,9 @@ void cpufreq_suspend(void)
>  			pr_err("%s: Failed to suspend driver: %p\n", __func__,
>  				policy);
>  	}
> +
> +suspend:
> +	cpufreq_suspended = true;
>  }
>  
>  /**
> 

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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