devicetree.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Sudeep Holla <sudeep.holla@arm.com>
To: Sowjanya Komatineni <skomatineni@nvidia.com>
Cc: thierry.reding@gmail.com, jonathanh@nvidia.com,
	daniel.lezcano@linaro.org, robh+dt@kernel.org,
	ksitaraman@nvidia.com, sanjayc@nvidia.com,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
	Sudeep Holla <Sudeep.Holla@arm.com>,
	linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-pm@vger.kernel.org, devicetree@vger.kernel.org
Subject: Re: [PATCH v1 3/5] dt-bindings: arm: Add cpu-idle-states to Tegra194 CPU nodes
Date: Tue, 16 Mar 2021 07:18:11 +0000	[thread overview]
Message-ID: <20210316071811.5mqcatmmbvrask2p@bogus> (raw)
In-Reply-To: <4b21f4c7-19cd-fcea-dd1b-9203be60a523@nvidia.com>

On Mon, Mar 15, 2021 at 11:13:24AM -0700, Sowjanya Komatineni wrote:
> Hi Sudeep,
>
> I see you are one of the maintainer of PSCI driver. Please add any other
> right persons if you think should also agree/comment.
>
> Can you please comment on below 2 items based on your feedback?
>
> 1. Can you please suggest on proper way of generalizing to pass state
> residency time run-time along with state during state enter?
>
> Not sure if any other drivers need this but for Tegra as MCE firmware is
> in-charge of states enter and decisions, passing run-time state residency
> from kernel to ATF is required and agree on not using power_state value for
> this which is against PSCI spec.
>

Yes, I prefer you need to get this added in the PSCI specification.
I have passed this thread to the author of the specification.

> 2. Regarding state thresholds, although state thresholds are policy related
> in Tegra cpu idle perspective these thresholds are platform specific based
> on use case and mainly for MCE firmware usage to decide on state transitions
> for core and core clusters as well.
>
From previous emails, I gather these can be moved to firmware and need not be
there in DT ?

> As these are Tegra platform specific, Please comment if any other concerns
> in having this configured by Tegra CPU Idle kernel driver.
>

I prefer not to have Tegra specific idle driver if we can get the necessary
changes in PSCI spec. We must then have just one PSCI idle driver in the
kernel.


> Based on my understanding only above issue-1 is PSCI compliant related.
> Please confirm.
>

Correct.

--
Regards,
Sudeep

  parent reply	other threads:[~2021-03-16  7:19 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-04  6:08 [PATCH v1 0/5] Add cpuidle support for Tegra194 Sowjanya Komatineni
2021-03-04  6:08 ` [PATCH v1 1/5] MAINTAINERS: Add Tegra CPUIDLE driver section Sowjanya Komatineni
2021-03-04  8:01   ` Daniel Lezcano
2021-03-04  6:08 ` [PATCH v1 2/5] firmware: tegra: Add Tegra194 MCE ARI driver Sowjanya Komatineni
2021-03-04  6:08 ` [PATCH v1 3/5] dt-bindings: arm: Add cpu-idle-states to Tegra194 CPU nodes Sowjanya Komatineni
2021-03-04 20:47   ` Rob Herring
2021-03-08  4:37   ` Sudeep Holla
2021-03-08 18:32     ` Sowjanya Komatineni
2021-03-10 23:19       ` Sowjanya Komatineni
2021-03-11  2:52       ` Sudeep Holla
2021-03-11 21:11         ` Sowjanya Komatineni
2021-03-16  5:38           ` Sudeep Holla
     [not found]           ` <08ac26c1-8257-4c6d-d274-595fee28a00f@nvidia.com>
2021-03-16  6:57             ` Sudeep Holla
     [not found]             ` <4b21f4c7-19cd-fcea-dd1b-9203be60a523@nvidia.com>
2021-03-15 19:26               ` Sowjanya Komatineni
2021-03-16  7:18               ` Sudeep Holla [this message]
2021-03-16 11:24                 ` Sowjanya Komatineni
2021-03-04  6:08 ` [PATCH v1 4/5] cpuidle: Add Tegra194 cpuidle driver Sowjanya Komatineni
2021-03-05 13:50   ` Dmitry Osipenko
2021-03-04  6:08 ` [PATCH v1 5/5] arm64: dts: tegra194: Add CPU idle states Sowjanya Komatineni

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210316071811.5mqcatmmbvrask2p@bogus \
    --to=sudeep.holla@arm.com \
    --cc=Lorenzo.Pieralisi@arm.com \
    --cc=daniel.lezcano@linaro.org \
    --cc=devicetree@vger.kernel.org \
    --cc=jonathanh@nvidia.com \
    --cc=ksitaraman@nvidia.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=linux-tegra@vger.kernel.org \
    --cc=robh+dt@kernel.org \
    --cc=sanjayc@nvidia.com \
    --cc=skomatineni@nvidia.com \
    --cc=thierry.reding@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).