[PATCH] thermal/drivers/cpufreq_cooling: Update cpufreq_state only if state has changed

[PATCH] thermal/drivers/cpufreq_cooling: Update cpufreq_state only if state has changed

[zhuguangqing83]

From: zhuguangqing <zhuguangqing@xiaomi.com>

If state has not changed successfully and we updated cpufreq_state,
next time when the new state is equal to cpufreq_state (not changed
successfully last time), we will return directly and miss a
freq_qos_update_request() that should have been.

Signed-off-by: zhuguangqing <zhuguangqing@xiaomi.com>
---
 drivers/thermal/cpufreq_cooling.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c
index cc2959f22f01..00dc26c33899 100644
--- a/drivers/thermal/cpufreq_cooling.c
+++ b/drivers/thermal/cpufreq_cooling.c
@@ -438,13 +438,12 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
 	if (cpufreq_cdev->cpufreq_state == state)
 		return 0;
 
-	cpufreq_cdev->cpufreq_state = state;
-
 	frequency = get_state_freq(cpufreq_cdev, state);
 
 	ret = freq_qos_update_request(&cpufreq_cdev->qos_req, frequency);
 
 	if (ret > 0) {
+		cpufreq_cdev->cpufreq_state = state;
 		cpus = cpufreq_cdev->policy->cpus;
 		max_capacity = arch_scale_cpu_capacity(cpumask_first(cpus));
 		capacity = frequency * max_capacity;
-- 
2.17.1

Re: [PATCH] thermal/drivers/cpufreq_cooling: Update cpufreq_state only if state has changed

[Viresh Kumar]

On 05-11-20, 19:19, zhuguangqing83@gmail.com wrote:
> From: zhuguangqing <zhuguangqing@xiaomi.com>

Maybe fix your name in your email client or git config? It should be
Zhuguangqing (with first letter in CAPITAL) and maybe add a second
name also (surname) in case you want/have it.

> If state has not changed successfully and we updated cpufreq_state,
> next time when the new state is equal to cpufreq_state (not changed
> successfully last time), we will return directly and miss a
> freq_qos_update_request() that should have been.
> 
> Signed-off-by: zhuguangqing <zhuguangqing@xiaomi.com>

Please find and add below details as well, they are helpful in fixing
the stable kernels.

Fixes: 5130802ddbb1 ("thermal: cpu_cooling: Switch to QoS requests for freq limits")
Cc: v5.4+ <stable@vger.kernel.org> # v5.4+

> ---
>  drivers/thermal/cpufreq_cooling.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c
> index cc2959f22f01..00dc26c33899 100644
> --- a/drivers/thermal/cpufreq_cooling.c
> +++ b/drivers/thermal/cpufreq_cooling.c
> @@ -438,13 +438,12 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
>  	if (cpufreq_cdev->cpufreq_state == state)
>  		return 0;
>  
> -	cpufreq_cdev->cpufreq_state = state;
> -
>  	frequency = get_state_freq(cpufreq_cdev, state);
>  
>  	ret = freq_qos_update_request(&cpufreq_cdev->qos_req, frequency);
>  

Now that you are going to resend it anyways, drop this blank line as
well and mention that in the commit log.

>  	if (ret > 0) {
> +		cpufreq_cdev->cpufreq_state = state;
>  		cpus = cpufreq_cdev->policy->cpus;
>  		max_capacity = arch_scale_cpu_capacity(cpumask_first(cpus));
>  		capacity = frequency * max_capacity;

Good catch Zhuguangqing. Thanks.

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh