linux-kernel - Re: [PATCH V4 2/2] base/drivers/arch_topology: Default dmips-mhz if they are not set in DT

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Message-ID: <1ad863c3-2c78-52a1-2f0f-b7a3cc3ad80d@linaro.org>
Date:   Mon, 26 Nov 2018 21:08:12 +0100
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     rjw@...ysocki.net, linux-kernel@...r.kernel.org,
        viresh.kumar@...aro.org, Chris Redpath <chris.redpath@...aro.org>,
        Quentin Perret <quentin.perret@...aro.org>,
        Amit Kucheria <amit.kucheria@...aro.org>,
        Nicolas Dechesne <nicolas.dechesne@...aro.org>,
        Niklas Cassel <niklas.cassel@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Sudeep Holla <sudeep.holla@....com>,
        Li Yang <leoyang.li@....com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>
Subject: Re: [PATCH V4 2/2] base/drivers/arch_topology: Default dmips-mhz if
 they are not set in DT


Hi Greg,

thanks for the review.

On 26/11/2018 16:06, Greg Kroah-Hartman wrote:
> On Mon, Nov 26, 2018 at 01:20:43PM +0100, Daniel Lezcano wrote:
>> --- a/drivers/base/arch_topology.c
>> +++ b/drivers/base/arch_topology.c
>> @@ -243,9 +243,20 @@ static int __init register_cpufreq_notifier(void)
>>  	 * until we have the necessary code to parse the cpu capacity, so
>>  	 * skip registering cpufreq notifier.
>>  	 */
>> -	if (!acpi_disabled || !raw_capacity)
>> +	if (!acpi_disabled)
>>  		return -EINVAL;
>>  
>> +	if (!raw_capacity) {
>> +
>> +		pr_info("cpu_capacity: No capacity defined in DT, set default "
>> +		       "values to %ld\n", SCHED_CAPACITY_SCALE);
> 
> Why the extra blank line?
> 
> And what is userspace going to do with this noise?  Is this an error?
> Just normal operation?  A device should never be saying anything to the
> log for normal boot functionality.  When is this called?

It is not an error but a fallback path. It is called at init time when
the cpufreq notifier is called and when either the DT read failed or
nothing is specified. I agree this is noise, I will remove the trace.

> And no need for the "cpu_capacity:" right?  Shouldn't the pr_info() line
> handle the prefix for you?

Ah, right I did not pay attention to the prefix and blindly copied the
line from somewhere else. I think it is better to drop this trace in any
case.

I will provide a patch setting the pr_fmt in a separate series.


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