linux-kernel - Re: [RFC PATCH 1/3] cpufreq: fix the return value in 'cpufreq_boost_set

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Message-ID: <881629ba-17fb-114c-858f-43b62e32b421@huawei.com>
Date:   Fri, 15 May 2020 09:28:22 +0800
From:   Xiongfeng Wang <wangxiongfeng2@...wei.com>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>
CC:     <viresh.kumar@...aro.org>, <Souvik.Chakravarty@....com>,
        <Thanu.Rangarajan@....com>, <Sudeep.Holla@....com>,
        <guohanjun@...wei.com>, <john.garry@...wei.com>,
        <jonathan.cameron@...wei.com>, <linux-pm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH 1/3] cpufreq: fix the return value in
 'cpufreq_boost_set_sw()'

Hi Rafael,

Thanks for your reply !

On 2020/5/14 21:54, Rafael J. Wysocki wrote:
> On Friday, May 8, 2020 11:11:02 AM CEST Xiongfeng Wang wrote:
>> When I try to add SW BOOST support for CPPC, I got the following error:
>> cpufreq: cpufreq_boost_trigger_state: Cannot enable BOOST
>> cpufreq: store_boost: Cannot enable BOOST!
>>
>> It is because return value 1 of 'freq_qos_update_request()' means the
>> effective constraint value has changed, not a error code on failures.
>> But for 'cpufreq_driver.set_boost()', a nonzero return value means
>> failure. So change 'ret' to zero when 'freq_qos_update_request()'
>> returns a positive value.
>>
>> Signed-off-by: Xiongfeng Wang <wangxiongfeng2@...wei.com>
>> ---
>>  drivers/cpufreq/cpufreq.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
>> index 4adac3a..475fb1b 100644
>> --- a/drivers/cpufreq/cpufreq.c
>> +++ b/drivers/cpufreq/cpufreq.c
>> @@ -2522,6 +2522,8 @@ static int cpufreq_boost_set_sw(int state)
>>  		ret = freq_qos_update_request(policy->max_freq_req, policy->max);
>>  		if (ret < 0)
>>  			break;
>> +		else
>> +			ret = 0;
>>  	}
>>  
>>  	return ret;
>>
> 
> I would change cpufreq_boost_trigger_state() to take the 1 into account properly
> instead.

Thanks for your suggestion. I will change it in the next version.

Thanks,
Xiongfeng

> 
> Thanks!
> 
> 
> 
> 
> .
>