From: Lukasz Majewski <l.majewski@samsung.com>
To: Viresh Kumar <viresh.kumar@linaro.org>, "Rafael J. Wysocki" <rjw@sisk.pl>,
        Zhang Rui <rui.zhang@intel.com>,
        Eduardo Valentin <eduardo.valentin@ti.com>
Cc: "cpufreq@vger.kernel.org" <cpufreq@vger.kernel.org>,
        Linux PM list <linux-pm@vger.kernel.org>,
        Jonghwa Lee <jonghwa3.lee@samsung.com>,
        Lukasz Majewski <l.majewski@samsung.com>, l.majewski@majess.pl,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Andre Przywara <andre.przywara@linaro.org>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Kukjin Kim <kgene.kim@samsung.com>,
        Myungjoo Ham <myungjoo.ham@samsung.com>
Subject: [PATCH v5 7/7] Documentation:cpufreq:boost: Update BOOST documentation
Date: Thu, 04 Jul 2013 10:50:30 +0200
Message-id: <1372927830-2949-8-git-send-email-l.majewski@samsung.com>
In-reply-to: <1372927830-2949-1-git-send-email-l.majewski@samsung.com>
References: <1370502472-7249-1-git-send-email-l.majewski@samsung.com>
 <1372927830-2949-1-git-send-email-l.majewski@samsung.com>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 3248
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Since the support for software and hardware controlled boosting has been
added, the corresponding Documentation entry had been updated.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>

---
Changes for v5:
- New patch

 Documentation/cpu-freq/boost.txt |   26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/Documentation/cpu-freq/boost.txt b/Documentation/cpu-freq/boost.txt
index 9b4edfc..dd62e13 100644
--- a/Documentation/cpu-freq/boost.txt
+++ b/Documentation/cpu-freq/boost.txt
@@ -17,8 +17,8 @@ Introduction
 Some CPUs support a functionality to raise the operating frequency of
 some cores in a multi-core package if certain conditions apply, mostly
 if the whole chip is not fully utilized and below it's intended thermal
-budget. This is done without operating system control by a combination
-of hardware and firmware.
+budget. The decision about boost disable/enable is made either at hardware
+(e.g. x86) or software (e.g ARM).
 On Intel CPUs this is called "Turbo Boost", AMD calls it "Turbo-Core",
 in technical documentation "Core performance boost". In Linux we use
 the term "boost" for convenience.
@@ -48,24 +48,24 @@ be desirable:
 User controlled switch
 ----------------------
 
-To allow the user to toggle the boosting functionality, the acpi-cpufreq
-driver exports a sysfs knob to disable it. There is a file:
+To allow the user to toggle the boosting functionality, the cpufreq core
+driver exports a sysfs knob to enable or disable it. There is a file:
 /sys/devices/system/cpu/cpufreq/boost
 which can either read "0" (boosting disabled) or "1" (boosting enabled).
-Reading the file is always supported, even if the processor does not
-support boosting. In this case the file will be read-only and always
-reads as "0". Explicitly changing the permissions and writing to that
-file anyway will return EINVAL.
+The file is exported only when cpufreq driver supports boosting.
+Explicitly changing the permissions and writing to that file anyway will
+return EINVAL.
 
 On supported CPUs one can write either a "0" or a "1" into this file.
 This will either disable the boost functionality on all cores in the
-whole system (0) or will allow the hardware to boost at will (1).
+whole system (0) or will allow the software or hardware to boost at will
+(1).
 
 Writing a "1" does not explicitly boost the system, but just allows the
-CPU (and the firmware) to boost at their discretion. Some implementations
-take external factors like the chip's temperature into account, so
-boosting once does not necessarily mean that it will occur every time
-even using the exact same software setup.
+CPU to boost at their discretion. Some implementations take external
+factors like the chip's temperature into account, so boosting once does
+not necessarily mean that it will occur every time even using the exact
+same software setup.
 
 
 AMD legacy cpb switch
-- 
1.7.10.4

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