linux-kernel - Re: [PATCH 0/2] fix some problems for cpufreq

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Message-ID: <547923F2.6000701@huawei.com>
Date:	Sat, 29 Nov 2014 09:40:02 +0800
From:	Wang Weidong <wangweidong1@...wei.com>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
CC:	<viresh.kumar@...aro.org>, <linux-pm@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <guohanjun@...wei.com>
Subject: Re: [PATCH 0/2] fix some problems for cpufreq

On 2014/11/29 9:26, Rafael J. Wysocki wrote:
> On Friday, November 28, 2014 10:43:37 AM Wang Weidong wrote:
>> Hi Rafael and Viresh
>>
>> Sorry to trouble you again. As for:
>> "acpi-cpufreq: get the cur_freq from acpi_processor_performance states"
>> I do it again, and add the other patch.
>>
>> patch #1: acpi-cpufreq: make the freq_table store the same freq value
>>
>> I think it can work. The set of available states which come
>> from acpi won't change. Just like the power would be remove,
>> the acpi driver will do that:
>> call
>>  ->acpi_processor_ppc_has_changed
>>  ->cpufreq_update_policy
>>  ->acpi_ppc_notifier_block.notifier_call
>>    ->acpi_processor_ppc_notifier
>>    ->cpufreq_verify_within_limits
>> The progress will change the policy's min_freq and max_freq
>> while it won't change the set of states(freq_tables).
> 
> OK, so the above information needs to go into the changelog of patch [1/2].
> Also, please clarify the problem description in that changelog, it is very
> difficult to understand the way it is now.
> 

sure, I should do it.

>> patch #2: cpufreq: show the real avail freqs with the freq_table
>>
>> when the min_freq and max_freq change, we should sync the availble
>> freqs.
> 
> Why?  Do any other cpufreq drivers do that?
> 

If some cpufreq drivers support several freqs like this:
1.05 Ghz 1.30Ghz 1.70GHz 2.10GHz 2.3GHz
           |                |
          min              max
So what the available freqs is 1.30GHz 1.70GHz 2.10GHz

when we do cpufreq-info or cat scaling_available_frequencies,
I think the available freqs table show only show these 3 value,
not all the values.

Wang,
Regards

> Rafael
> 
> 
> .
> 


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