From: Nishanth Menon <nm@ti.com>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux PM list <linux-pm@vger.kernel.org>
Subject: Re: [GIT PULL] ACPI and power management fixes for v3.9-rc1
Date: Tue, 26 Feb 2013 10:10:49 -0600 [thread overview]
Message-ID: <20130226161049.GA9303@kahuna> (raw)
In-Reply-To: <2223198.XmyRLgb3Gv@vostro.rjw.lan>
On 16:55-20130226, Rafael J. Wysocki wrote:
> On Monday, February 25, 2013 09:31:45 PM Linus Torvalds wrote:
> > On Mon, Feb 25, 2013 at 7:17 PM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
[..]
>
> > This has become a huge problem, to the point that we have a
> > "Documentation/power/opp.txt" file THAT NEVER CLEARLY STATES WHAT THE
> > F*CK OPP ACTUALLY MEANS! What nice "documentation".
>
> It says that in "Introduction", but it would be clearer if the title of the
> doc was something like "Operating Performance Points (OPP) Library". Nishanth?
Yes indeed. Will the following help? I can post it as an official patch
if the direction is proper.
diff --git a/Documentation/power/opp.txt b/Documentation/power/opp.txt
index 3035d00..4a17443 100644
--- a/Documentation/power/opp.txt
+++ b/Documentation/power/opp.txt
@@ -1,5 +1,5 @@
*=============*
-* OPP Library *
+* Operating Performance Points (OPP) Library *
*=============*
(C) 2009-2010 Nishanth Menon <nm@ti.com>, Texas Instruments Incorporated
@@ -16,6 +16,8 @@ Contents
1. Introduction
===============
+1.1 What is an Operating Performance Point (OPP)?
+
Complex SoCs of today consists of a multiple sub-modules working in conjunction.
In an operational system executing varied use cases, not all modules in the SoC
need to function at their highest performing frequency all the time. To
@@ -25,6 +27,16 @@ more. The set of discrete tuples consisting of frequency and voltage pairs that
the device will support per domain are called Operating Performance Points or
OPPs.
+As an example:
+MPU device supports {300MHz at minimum voltage of 1V}, {800MHz at minimum
+voltage of 1.2V}, {1GHz at minimum voltage of 1.3V}
+We can represent these as three OPPs
+{300000, 1000000}
+{800000, 1200000}
+{1000000, 1300000}
+
+1.2 Operating Performance Points Library
+
OPP library provides a set of helper functions to organize and query the OPP
information. The library is located in drivers/base/power/opp.c and the header
is located in include/linux/opp.h. OPP library can be enabled by enabling
--
Regards,
Nishanth Menon
next prev parent reply other threads:[~2013-02-26 16:10 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-24 14:29 [GIT PULL] ACPI and power management fixes for v3.9-rc1 Rafael J. Wysocki
2013-02-26 3:17 ` Rafael J. Wysocki
2013-02-26 5:31 ` Linus Torvalds
2013-02-26 15:55 ` Rafael J. Wysocki
2013-02-26 16:10 ` Nishanth Menon [this message]
2013-02-26 16:27 ` Linus Torvalds
2013-02-26 16:28 ` Linus Torvalds
2013-02-26 16:37 ` Tejun Heo
2013-02-26 16:47 ` Linus Torvalds
2013-02-26 16:58 ` Tejun Heo
2013-02-26 17:59 ` Jeff Garzik
2013-03-01 1:32 ` [PATCH] [libata] Avoid specialized TLA's in ZPODD's Kconfig Aaron Lu
2013-03-01 13:10 ` Sergei Shtylyov
2013-03-02 5:00 ` [PATCH v2] " Aaron Lu
2013-03-04 22:14 ` Jeff Garzik
2013-02-27 2:24 ` [GIT PULL] ACPI and power management fixes for v3.9-rc1 Aaron Lu
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=20130226161049.GA9303@kahuna \
--to=nm@ti.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=rjw@sisk.pl \
--cc=torvalds@linux-foundation.org \
/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