linux-kernel - Re: [PATCH v4 06/12] cpufreq: qcom: Update the bandwidth levels on frequency change

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Date:   Tue, 26 May 2020 23:18:19 +0530
From:   Sibi Sankar <sibis@...eaurora.org>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     sboyd@...nel.org, georgi.djakov@...aro.org,
        bjorn.andersson@...aro.org, saravanak@...gle.com, mka@...omium.org,
        nm@...com, agross@...nel.org, david.brown@...aro.org,
        robh+dt@...nel.org, mark.rutland@....com, rjw@...ysocki.net,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        dianders@...omium.org, vincent.guittot@...aro.org,
        amit.kucheria@...aro.org, ulf.hansson@...aro.org,
        lukasz.luba@....com, sudeep.holla@....com
Subject: Re: [PATCH v4 06/12] cpufreq: qcom: Update the bandwidth levels on
 frequency change

On 2020-05-05 12:49, Sibi Sankar wrote:
> On 2020-05-05 10:20, Viresh Kumar wrote:
>> On 05-05-20, 01:52, Sibi Sankar wrote:
>>> Add support to parse optional OPP table attached to the cpu node when
>>> the OPP bandwidth values are populated. This allows for scaling of
>>> DDR/L3 bandwidth levels with frequency change.
>>> 
>>> Signed-off-by: Sibi Sankar <sibis@...eaurora.org>
>> 
>> What about using opp_set_rate instead ?
> 
> I can't use opp_set_rate since
> the cpu dev does not have a
> clock associated with it and the
> scaling is done through writing
> on perf state register.

Viresh,

https://patchwork.kernel.org/cover/11548479/
GPU driver uses Georgi's series
for scaling and will need a way to
remove the icc votes in the suspend
path, (this looks like a pattern
that might be used by other clients
as well) I could probably update
opp_set_bw to support removing bw
when NULL opp is specified. Similarly
opp_set_rate will need to support
set bw to 0 when set_rate is passed
0 as target freq for the same use case.

-- 
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a Linux Foundation Collaborative Project.