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Subject: Re: [PATCH V8 1/8] PM / devfreq: Add cpu based scaling support to
 passive_governor
To:     "andrew-sh.cheng" <andrew-sh.cheng@mediatek.com>,
        Hsin-Yi Wang <hsinyi@google.com>
Cc:     MyungJoo Ham <myungjoo.ham@samsung.com>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Nishanth Menon <nm@ti.com>, Stephen Boyd <sboyd@kernel.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>, linux-pm@vger.kernel.org,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
        srv_heupstream@mediatek.com, Sibi Sankar <sibis@codeaurora.org>
From:   Chanwoo Choi <cw00.choi@samsung.com>
Organization: Samsung Electronics
Message-ID: <316af76d-fc63-eeff-7419-cb4b44ee62fe@samsung.com>
Date:   Mon, 31 May 2021 16:56:33 +0900
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Precedence: bulk

Hi,

On 5/31/21 12:22 PM, andrew-sh.cheng wrote:
> On Wed, 2021-05-26 at 12:08 +0900, Chanwoo Choi wrote:
>> Hi,
>> On 5/26/21 11:22 AM, andrew-sh.cheng wrote:
>>> On Thu, 2021-04-08 at 11:47 +0900, Chanwoo Choi wrote:
>>>> On 4/1/21 9:16 AM, Chanwoo Choi wrote:
>>>>> On 3/31/21 10:03 PM, andrew-sh.cheng wrote:
>>>>>> On Wed, 2021-03-31 at 17:35 +0900, Chanwoo Choi wrote:
>>>>>>> On 3/31/21 5:27 PM, Chanwoo Choi wrote:
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>> On 3/31/21 5:03 PM, andrew-sh.cheng wrote:
>>>>>>>>> On Thu, 2021-03-25 at 17:14 +0900, Chanwoo Choi wrote:
>>>>>>>>>> Hi,
>>>>>>>>>>
>>>>>>>>>> You are missing to add these patches to linux-pm mailing list.
>>>>>>>>>> Need to send them to linu-pm ML.
>>>>>>>>>>
>>>>>>>>>> Also, before received this series, I tried to clean-up these patches
>>>>>>>>>> on testing branch[1]. So that I add my comment with my clean-up case.
>>>>>>>>>> [1] https://urldefense.com/v3/__https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git/log/?h=devfreq-testing-passive-gov__;!!CTRNKA9wMg0ARbw!zIrzeDp9vPnm1_SDzVPuzqdHn3zWie9DnfBXaA-j9-CSrVc6aR9_rJQQiw81_CgAPh9XRRs$ 
>>>>>>>>>>
>>>>>>>>>> And 'Saravana Kannan <skannan@codeaurora.org>' is wrong email address.
>>>>>>>>>> Please update the email or drop this email.
>>>>>>>>>
>>>>>>>>> Hi Chanwoo,
>>>>>>>>>
>>>>>>>>> Thank you for the advices.
>>>>>>>>> I will resend patch v9 (add to linux-pm ML), remove this patch, and note
>>>>>>>>> that my patch set base on
>>>>>>>>> https://urldefense.com/v3/__https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git/log/?h=devfreq-testing-passive-gov__;!!CTRNKA9wMg0ARbw!yUlsuxrL5PcbF7o6A9DlCfvoA6w8V8VXKjYIybYyiJg3D0HM-lI2xRuxLUV6b3UJ8WFhg_g$ 
>>>>>>>>
>>>>>>>> I has not yet test this patch[1] on devfreq-testing-passive-gov branch.
>>>>>>>> So that if possible, I'd like you to test your patches with this patch[1] 
>>>>>>>> and then if there is no problem, could you send the next patches with patch[1]?
>>>>>>>>
>>>>>>>> [1]https://urldefense.com/v3/__https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git/commit/?h=devfreq-testing-passive-gov&id=39c80d11a8f42dd63ecea1e0df595a0ceb83b454__;!!CTRNKA9wMg0ARbw!yUlsuxrL5PcbF7o6A9DlCfvoA6w8V8VXKjYIybYyiJg3D0HM-lI2xRuxLUV6b3UJR2cQqZs$ 
>>>>>>>
>>>>>>>
>>>>>>> Sorry for the confusion. I make the devfreq-testing-passive-gov[1]
>>>>>>> branch based on latest devfreq-next branch.
>>>>>>> [1] https://urldefense.com/v3/__https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git/log/?h=devfreq-testing-passive-gov__;!!CTRNKA9wMg0ARbw!yUlsuxrL5PcbF7o6A9DlCfvoA6w8V8VXKjYIybYyiJg3D0HM-lI2xRuxLUV6b3UJ8WFhg_g$ 
>>>>>>>
>>>>>>> First of all, if possible, I want to test them[1] with your patches in this series.
>>>>>>> And then if there are no any problem, please let me know. After confirmed from you,
>>>>>>> I'll send the patches of devfreq-testing-passive-gov[1] branch.
>>>>>>> How about that?
>>>>>>>
>>>>>> Hi Chanwoo~
>>>>>>
>>>>>> We will use this on Google Chrome project.
>>>>>> Google Hsin-Yi has test your patch + my patch set v8 [2~8]
>>>>>>
>>>>>>     make sure cci devfreqs runs with cpufreq.
>>>>>>     suspend resume
>>>>>>     speedometer2 benchmark
>>>>>> It is okay.
>>>>>>
>>>>>> Please send the patches of devfreq-testing-passive-gov[1] branch.
>>>>>>
>>>>>> I will send patch v9 base on yours latter.
>>>>>
>>>>> Thanks for your test. I'll send the patches today.
>>>>
>>>> I'm sorry for delay because when I tested the patches
>>>> for devfreq parent type on Odroid-xu3, there are some problem
>>>> related to lazy linking of OPP. So I'm trying to analyze them.
>>>> Unfortunately, we need to postpone these patches to next linux
>>>> version.
>>>>
>>> Hi Chanwoo Choi~
>>>
>>> It is said that you are busy on another task recently.
>>> May I know your plan on this patch?
>>> Thank you.
>>
>> Sorry for late work. I have a question.
>> When I tested exynos-bus.c with adding the 'required-opp' property
>> on odroid-xu3 board. I got some fail about 
>>
>> When calling _set_required_opps(), always _set_required_opp() returns
>> -EBUSY error because of following lazy linking case[1].
>>
>> [1] https://urldefense.com/v3/__https://elixir.bootlin.com/linux/v5.13-rc3/source/drivers/opp/core.c*L896__;Iw!!CTRNKA9wMg0ARbw!3eNxwDZRy-Ev5BHGxT-BxCz4qrNy0NZohQuBGW36krkwOkl_WX8yBmxlqSk9hxp_kxspMJI$ 
>>
>> /* required-opps not fully initialized yet */
>> if (lazy_linking_pending(opp_table))
>> 	return -EBUSY;  
>>
>>
>> For calling dev_pm_opp_of_add_table(), lazy_link_required_opp_table() function
>> will be called. But, there is constraint[2]. If is_genpd of opp_table is false,
>> driver/opp/of.c cannot resolve the lazy linking issue.
>>
>> [2]  https://urldefense.com/v3/__https://elixir.bootlin.com/linux/v5.13-rc3/source/drivers/opp/of.c*L386__;Iw!!CTRNKA9wMg0ARbw!3eNxwDZRy-Ev5BHGxT-BxCz4qrNy0NZohQuBGW36krkwOkl_WX8yBmxlqSk9hxp_QFUVY9E$ 
>>
>> /* Link required OPPs for all OPPs of the newly added OPP table */
>> static void lazy_link_required_opp_table(struct opp_table *new_table)
>> {
>> 	struct opp_table *opp_table, *temp, **required_opp_tables;
>> 	struct device_node *required_np, *opp_np, *required_table_np;
>> 	struct dev_pm_opp *opp;
>> 	int i, ret;
>>
>> 	/*
>> 	 * We only support genpd's OPPs in the "required-opps" for now,
>> 	 * as we don't know much about other cases.
>> 	 */
>> 	if (!new_table->is_genpd)
>> 		return;
>>
>> Even if this case, there are no problem on your test case?
>>
> 
> Hi Chanwoo~
> Sorry for late reply.
> Yes, we meet similar issue.
> Google member Hsin-Yi had helped deal with this issue on Chrome project.
> 
> Patch segment:
> @ /drivers/opp/of.c
> 
> /* Link required OPPs for all OPPs of the newly added OPP table */
> static void lazy_link_required_opp_table(struct opp_table *new_table)
> {
> 	struct opp_table *opp_table, *temp, **required_opp_tables;
> 	struct device_node *required_np, *opp_np, *required_table_np;
> 	struct dev_pm_opp *opp;
> 	int i, ret;
> 
> +	/*
> +	 * We only support genpd's OPPs in the "required-opps" for now,
> +	 * as we don't know much about other cases.
> +	 */
> +	if (!new_table->is_genpd)
> +		return;
> 
> 
> Hsin-Yi replied this issue in the discussion list in the original lazy
> link thread:
> https://patchwork.kernel.org/project/linux-pm/patch/20190717222340.137578-4-saravanak@google.com/#23932203
> 
> Loop Hsin-YI here.
> You can discuss with her if needing more detail.
> 
> Thank you both.
> 

Thanks. First of all, we need to resolve and discuss this issue.


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics