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Message-ID: <fb9b21f6-4c73-4a85-93cc-56e7c44359cb@arm.com>
Date: Wed, 20 Mar 2024 14:15:54 +0000
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Subject: Re: [PATCH v1] thermal: devfreq_cooling: Fix perf state when
 calculate dfc res_util
Content-Language: en-US
To: Ye Zhang <ye.zhang@rock-chips.com>
Cc: tao.huang@rock-chips.com, heiko@sntech.de, rui.zhang@intel.com,
 finley.xiao@rock-chips.com, linux-rockchip@lists.infradead.org,
 linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
 daniel.lezcano@linaro.org, rafael@kernel.org
References: <20240320075704.1924897-1-ye.zhang@rock-chips.com>
From: Lukasz Luba <lukasz.luba@arm.com>
In-Reply-To: <20240320075704.1924897-1-ye.zhang@rock-chips.com>
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Hi Ye,

On 3/20/24 07:57, Ye Zhang wrote:
> The EM power table is sorted ascending，can't index the table by cooling
> device state，so convert cooling state to performance state by
> dfc->max_state - dfc->capped_state.
> 
> Signed-off-by: Ye Zhang <ye.zhang@rock-chips.com>
> ---
>   drivers/thermal/devfreq_cooling.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c
> index 50dec24e967a..8fd7cf1932cd 100644
> --- a/drivers/thermal/devfreq_cooling.c
> +++ b/drivers/thermal/devfreq_cooling.c
> @@ -214,7 +214,7 @@ static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cd
>   
>   		res = dfc->power_ops->get_real_power(df, power, freq, voltage);
>   		if (!res) {
> -			state = dfc->capped_state;
> +			state = dfc->max_state - dfc->capped_state;
>   
>   			/* Convert EM power into milli-Watts first */
>   			rcu_read_lock();

Thank you for the patch. Good catch! It's under the device driver
callback optional thing: get_real_power().

Please send the v2 with extended explanation about the section
of the code, which is triggered by the get_real_power() presence.
Also, please add the tags, so it can be collected by stable kernel.

Fixes: 615510fe13bd2434610 ("thermal: devfreq_cooling: remove old power 
model and use EM")
Cc: 5.11+ <stable@vger.kernel.org> # 5.11+

BTW, how did you trigger that issue? Do you have such a driver
which provides this get_real_power() callback?

Regards,
Lukasz