linux-kernel - Re: [PATCH 1/2] dt-bindings: arm: idle-states: Add idle-state-disabled property

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Message-ID: <5820345a-4207-3b12-87eb-098bac4ef4e8@quicinc.com>
Date:   Fri, 16 Jun 2023 11:26:18 +0530
From:   Tushar Nimkar <quic_tnimkar@...cinc.com>
To:     Sudeep Holla <sudeep.holla@....com>
CC:     "Rafael J . Wysocki" <rafael@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        <linux-pm@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <quic_lsrao@...cinc.com>,
        <quic_mkshah@...cinc.com>, <devicetree@...r.kernel.org>
Subject: Re: [PATCH 1/2] dt-bindings: arm: idle-states: Add
 idle-state-disabled property


Thanks for review Sundeep,

On 6/15/2023 2:26 PM, Sudeep Holla wrote:
> On Thu, Jun 08, 2023 at 02:25:42PM +0530, Tushar Nimkar wrote:
>> +      idle-state-disabled:
>> +        description: |
>> +          If present the idle state stays disabled. It can be enabled back from
>> +          shell using below command.
>> +          echo N > /sys/devices/system/cpu/cpuX/cpuidle/stateX/disable
>> +        type: boolean
>> +
> 
> This is clearly a policy and not a hardware or firmware feature to expose
> in the device tree. So NACK, why can't you load it modules if you don't want
> idle states in the boot.
> 
Attempt of making cpuidle governors to modular was rejected in past [2]

[2] 
https://lore.kernel.org/lkml/1637830481-21709-1-git-send-email-quic_mkshah@quicinc.com/#t

> It is same as choosing any default governor or performance states, will you
> add those next ? It is simply policy not a feature/property to be exposed
> in the device tree.
> 
> --
> Regards,
> Sudeep

Thanks,
Tushar