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Subject: Re: [PATCH 1/2] PM: docs: Describe high-level PM strategies and sleep
 states
From: Markus Heiser <markus.heiser@darmarit.de>
In-Reply-To: <2269280.4Jsh6Gf7ai@aspire.rjw.lan>
Date: Mon, 21 Aug 2017 11:51:48 +0200
Cc: Linux PM <linux-pm@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux Doc Mailing List <linux-doc@vger.kernel.org>
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References: <3053012.25nKXRPPaK@aspire.rjw.lan>
 <2269280.4Jsh6Gf7ai@aspire.rjw.lan>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Jonathan Corbet <corbet@lwn.net>
Sender: linux-kernel-owner@vger.kernel.org
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Lines: 185

Hi Rafael,

great work, helps me and the world saving fossil fuels ;)

> Am 20.08.2017 um 18:05 schrieb Rafael J. Wysocki <rjw@rjwysocki.net>:
> 
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> Reorganize the power management part of admin-guide by adding a
> description of major power management strategies supported by the
> kernel (system-wide and working-state power management) to it and
> dividing the rest of the material into the system-wide PM and
> working-state PM chapters.
> 
> On top of that, add a description of system sleep states to the
> system-wide PM chapter.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
> Documentation/admin-guide/pm/index.rst         |    5 
> Documentation/admin-guide/pm/sleep-states.rst  |  234 +++++++++++++++++++++++++
> Documentation/admin-guide/pm/strategies.rst    |   52 +++++
> Documentation/admin-guide/pm/system-wide.rst   |   15 +
> Documentation/admin-guide/pm/working-state.rst |   16 +
> 5 files changed, 320 insertions(+), 2 deletions(-)
> 
> Index: linux-pm/Documentation/admin-guide/pm/index.rst
> ===================================================================
> --- linux-pm.orig/Documentation/admin-guide/pm/index.rst
> +++ linux-pm/Documentation/admin-guide/pm/index.rst
> @@ -5,8 +5,9 @@ Power Management
> .. toctree::
>    :maxdepth: 2
> 
> -   cpufreq
> -   intel_pstate
> +   strategies
> +   system-wide
> +   working-state
> 
> .. only::  subproject and html

BTW: lets drop this C&P 'only' block here. Subprojects are only where a
Documentation/*/conf.py exists. The build does not have sub-sub-projects
at Documentation/*/*/conf.py level.


> Index: linux-pm/Documentation/admin-guide/pm/sleep-states.rst
> ===================================================================
> --- /dev/null
> +++ linux-pm/Documentation/admin-guide/pm/sleep-states.rst
> @@ -0,0 +1,234 @@
> +===================
> +System Sleep States
> +===================
> +
> +::
> +
> + Copyright (c) 2017 Intel Corp., Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> +
> +Sleep states are global low-power states of the entire system in which user
> +space code cannot be executed and the overall system activity is significantly
> +reduced.
> +
> +
> +

[...]
> Index: linux-pm/Documentation/admin-guide/pm/system-wide.rst
> ===================================================================
> --- /dev/null
> +++ linux-pm/Documentation/admin-guide/pm/system-wide.rst
> @@ -0,0 +1,15 @@
> +============================
> +System-Wide Power Management
> +============================
> +
> +.. toctree::
> +   :maxdepth: 2
> +
> +   sleep-states
> +
> +.. only::  subproject and html
> +
> +   Indices
> +   =======
> +
> +   * :ref:`genindex`

Same here, lets drop the 'only' block.


> Index: linux-pm/Documentation/admin-guide/pm/working-state.rst
> ===================================================================
> --- /dev/null
> +++ linux-pm/Documentation/admin-guide/pm/working-state.rst
> @@ -0,0 +1,16 @@
> +==============================
> +Working-State Power Management
> +==============================
> +
> +.. toctree::
> +   :maxdepth: 2
> +
> +   cpufreq
> +   intel_pstate
> +
> +.. only::  subproject and html
> +
> +   Indices
> +   =======
> +
> +   * :ref:`genindex`

Same here, lets drop the 'only' block.

> Index: linux-pm/Documentation/admin-guide/pm/strategies.rst
> ===================================================================
> --- /dev/null
> +++ linux-pm/Documentation/admin-guide/pm/strategies.rst
> @@ -0,0 +1,52 @@
> +===========================
> +Power Management Strategies
> +===========================
> +
> +::
> +
> + Copyright (c) 2017 Intel Corp., Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> +
> +The Linux kernel supports two major high-level power management strategies.
> +
> +One of them is based on using global low-power states of the whole system in
> +which user space code cannot be executed and the overall system activity is
> +significantly reduced, referred to as :doc:`sleep states <sleep-states>`.  The
> +kernel puts the system into one of these states when requested by user space
> +and the system stays in it until a special signal is received from one of
> +designated devices, triggering a transition to the ``working state`` in which
> +user space code can run.  Because sleep states are global and the whole system
> +is affected by the state changes, this strategy is referred to as the
> +:doc:`system-wide power management <system-wide>`.

I really appreciate your hyper-ref markup using :doc:`Foo <foo>` and `Bar`_
it is very clear when reading the raw text files in the source tree. I think
this has its value, but it also has its drawbacks when chapters are renamed
or moved from one file to another. Thats, why I recommend using explicitly
anchors / may be the maintainer Jon can give us his assessment. What I mean::

.. _foo:

Foo
===

lorem see :ref:`bar`

.. _bar:

Bar
===

ipsum see :ref:`foo`

With explicitly anchors:

- there is no need to track when a chapter is renamed
- or moved to another file,
- same to renaming files
- with intersphinx [1] other projects can link to such anchors

[1] http://www.sphinx-doc.org/en/stable/ext/intersphinx.html


> +
> +The other strategy, referred to as the
> +:doc:`working-state power management <working-state>`,

Even if you use :ref: or :doc: both are line-break-safe ...

+The other strategy, referred to as the :doc:`working-state power
+management <working-state>`, ...

.. should work.

Thanks!

-- Markus --