Smartreflex

(New page: ==The official explanation== ::''"SmartReflex is an advanced, multi-level and multi-parameter power management approach that can be found at some TI DSPs of the OMAP35x series."''[http://...)
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'''TL;DR.''' SmartReflex is a nifty way of scaling the voltage of the processor in a way similar to frequency scaling.  That is, voltage is increased as it is required.  Conversely it is decreased as it is not required.  Most users report that this has lead to an increase of around 1/3 battery life. (DISCLAIMER:1/3 battery life is dependent on a particular users set up and style of use.)
'''TL;DR.''' SmartReflex is a nifty way of scaling the voltage of the processor in a way similar to frequency scaling.  That is, voltage is increased as it is required.  Conversely it is decreased as it is not required.  Most users report that this has lead to an increase of around 1/3 battery life. (DISCLAIMER:1/3 battery life is dependent on a particular users set up and style of use.)
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==Stock Nokia kernel==
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This module adjusts OMAP3 VDD1 and VDD2 operating voltages around the nominal values of current operating point depending on silicon characteristics and operating conditions.
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Smart reflex has been considered broken for a long time.  Using the stock Nokia kernel it can only be activated up to 805MHz at most.  The Stock Nokia kernel implementation of SmartReflex is to be considered broken and its use is to be avoided.
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==SR on the Stock Nokia kernel==
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Smartreflex has been considered broken for a long time.  Using the stock Nokia kernel it can only be activated up to 805MHz at most.  The Stock Nokia kernel implementation of SmartReflex is to be considered broken and its use is to be avoided.
 +
 
 +
 
 +
Due to it's instability and multiple bug reports:-
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''"Nokia decided that SR will be kept disabled. In the next public update (PR 1.3) it will be made possible for advanced users to enable it if wanted."''
==Kernel Power==
==Kernel Power==
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Since kernel power 50 (KP50), despite some disagreements amongst some of the more senior Maemo developers, SmartReflex can now be considered stable up 900MHz.
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Since [[Kernel Power]] 50 (KP50), despite some disagreements amongst some of the more senior Maemo developers, SmartReflex can now be considered stable up 900MHz.
 +
 
 +
*''I know I just said SR is stable up to 900MHz however some users have reported that on their devices SR is only stable up to lower frequencies (720-805MHz for example).  For more examples on tuning SR see the KP50 article.
 +
''
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==Enabling Smartreflex==
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===Terminal===
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Assuming you are using [[Kernel Power]] the instruction for use are:-
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[[http://wiki.maemo.org/Kernel_Power#Use_of_kernel-config Use of Kernel Power Configuration]]
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===Alternative Terminal Method===
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This alternative method can be used even if Stock Kernel is used.
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sudo leafpad /etc/pmconfig
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==So how do I enable it?==
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Use leafpad text editor to change, sr_vdd_autocomp to:-
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Assuming you are using KP50 there are several ways you can enable SR.
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sr_vdd1_autocomp 1
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sr_vdd2_autocomp 1
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''list methods here!''
 
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===Caveats!===
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===GUI===
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*I know I just said SR is stable up to 900MHz however some users have reported that on their devices SR is only stable up to lower frequencies (720-805MHz for example). For more example on tuning SR see the KP50 article.
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[[http://maemo.org/downloads/product/Maemo5/qcpufreq/ QCPUFreq]] application has an option to enable Smartreflex via GUI.
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However it currently only changes VDD1 values.

Revision as of 16:23, 31 May 2012

Contents

The official explanation

"SmartReflex is an advanced, multi-level and multi-parameter power management approach that can be found at some TI DSPs of the OMAP35x series."[1]

TL;DR. SmartReflex is a nifty way of scaling the voltage of the processor in a way similar to frequency scaling. That is, voltage is increased as it is required. Conversely it is decreased as it is not required. Most users report that this has lead to an increase of around 1/3 battery life. (DISCLAIMER:1/3 battery life is dependent on a particular users set up and style of use.)

This module adjusts OMAP3 VDD1 and VDD2 operating voltages around the nominal values of current operating point depending on silicon characteristics and operating conditions.

SR on the Stock Nokia kernel

Smartreflex has been considered broken for a long time. Using the stock Nokia kernel it can only be activated up to 805MHz at most. The Stock Nokia kernel implementation of SmartReflex is to be considered broken and its use is to be avoided.


Due to it's instability and multiple bug reports:-

"Nokia decided that SR will be kept disabled. In the next public update (PR 1.3) it will be made possible for advanced users to enable it if wanted."

Kernel Power

Since Kernel Power 50 (KP50), despite some disagreements amongst some of the more senior Maemo developers, SmartReflex can now be considered stable up 900MHz.

  • I know I just said SR is stable up to 900MHz however some users have reported that on their devices SR is only stable up to lower frequencies (720-805MHz for example). For more examples on tuning SR see the KP50 article.

Enabling Smartreflex

Terminal

Assuming you are using Kernel Power the instruction for use are:-

[Use of Kernel Power Configuration]


Alternative Terminal Method

This alternative method can be used even if Stock Kernel is used. 

sudo leafpad /etc/pmconfig

Use leafpad text editor to change, sr_vdd_autocomp to:- 

sr_vdd1_autocomp 1
sr_vdd2_autocomp 1


GUI

[QCPUFreq] application has an option to enable Smartreflex via GUI. However it currently only changes VDD1 values.

Retrieved from "http://wiki.maemo.org/Smartreflex"