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==Overclocking==

This page is about overclocking the [[Nokia N900|N900]]. For the N8x0 see [http://talk.maemo.org/showthread.php?t=12464 this thread on talk.maemo.org]

&#x23; ''WORK IN PROGRESS, HELP IF YOU WANT''

Overclocking is discussed in [http://talk.maemo.org/showthread.php?t=39753 this thread].
Benchmark results can be found [http://talk.maemo.org/showthread.php?p=605189 here].
If you're more interested in power saving read [http://talk.maemo.org/showthread.php?t=49654 this].

==Warnings==

* Overclocking WILL VOID YOUR WARRANTY. Your warranty does not cover running the device beyond the specifications.
* The lifetime of your device may get reduced (see below)
* Your data might get corrupted (for example, file system corruption)
* Every device is an individual, what is stable for others might not be for you
* If you encounter ANY unusual problems, lower your clock frequency
* You do it at your own responsibility. No whining afterwards. If you're unsure, don't do it.
* [http://depot.javispedro.com/nit/thewarningtm.jpeg Nokia's overclocking warning]: 500MHz is the normal frequency. Everything above is not good for your device, even with the stock kernel.
* Igor Stoppa's [http://talk.maemo.org/showpost.php?p=596149&postcount=904 warning] and [http://talk.maemo.org/showpost.php?p=603833&postcount=66 comment]
* [http://talk.maemo.org/showpost.php?p=596274&postcount=937 chip vendors specs]

==Lifetime, warranty and damage==

* The expected lifetime '''all''' devices is limited due to wear.
* It is usually much longer (several years) than the warranty period, so that even with heavy use within the specifications it would not fail before warranty ends.
* With overclocking users may see considerable speed improvements and lower latency in user experience which could extend the actual lifetime (of being used) as the device could keep up with the newer models.
* Naive overclocking with stock voltages is definitely bad for most components in your device, especially if the device is continuously locked at high frequencies with high load (see TI specs).
* Specifications give guarantees for the worst-case scenarios that are covered by the warranty. The best-case scenario may be different for every device but is not covered by warranty.
* However, there is an open debate whether '''mild''' (<40%) overclocking with lower voltages (undervolting) does actually harm or is even less harmful than the stock settings.
* Evidence for or against damages (esp. with undervolting) in the N900 is currently absent and will probably only be available when the device is no longer on the market.
* Therefore, if you are unsure and you want to avoid potential damages, do not overclock!

==Overclocking, bugzilla & errors==

* Running a device overclocked for long periods of time could produce unwanted side effects. If you are expiriencing errors following Overclocking and intend to report those errors to talk.maemo.org or bugzilla, please consider the following :
**Errors induced by overclocking will not always appear to be as such.
**It will be considered a good idea to reproduce your error / problem on a device which has not been overclocked AT ALL before proceeding with actions regarding your problem.
**In the event you have decided to file a bug report or open a thread about your problem, please add a note to that report, mentioning that you are infact running your device overclocked.  Please also provide details about the period and amount of overclocking used.
*The reason for these requirements is that there many problems pending for developer's attention. The priority is to work on problems not related to overclocking, since the majority of users are not overclocking their devices.

==Available kernels==

Overclocking requires installation of a custom kernel. There are two types of kernels:
# modified PR1.1 kernels by Lehto and others. The only difference from the stock Nokia kernel is the change of the available hardcoded frequencies.
# enhanced kernels by titan. They are compatible with PR1.2 (!), contain lots of additional features (IPv6, NAT etc) and bugfixes. In addition they include a large set of possible frequencies (125MHz-1.15GHz) which you manually set and try out without flashing a new kernel. The defaults are set to the standard 250-600MHz range. The kernel can be installed via HAM from the [[extras-devel]] catalog.

=== Jakiman's Guide to Overclocking for Newcomers ===

[http://talk.maemo.org/showpost.php?p=595582&postcount=774 Jakiman's Overclock Guide / Summary] (constantly updated)

=== Installation of Lehto's PR1.1 kernels ===

[http://talk.maemo.org/showpost.php?p=594200&postcount=309 Lehto's Kernels]

=== Installation of titan's enhanced kernels ===

This kernel makes it possible to dynamically change the maximum frequency up to 1.15GHz (supported frequencies are 125,250,500,550,600,700,750,805,850,900,950,1000,1100,1150MHz).

see the separate page for this kernel: [[Kernel_Power]]

[http://talk.maemo.org/showthread.php?t=43420 talk.maemo.org: Discussion of the enhanced kernel]

==Additional information and hints==

# the frequencies available in the Nokia kernel are: 250, 500, 550 and 600MHz.
# the CPU does '''NOT IDLE''' at the lowest frequency (250MHz) but it '''SLEEPS''' at 0MHz! Thus reducing the lowest frequency would not reduce power consumption. It is only activated during low workload and may actually consume more power than a higher frequency, as it takes more time to go back to sleep/idle state.
# setting the lowest frequency to 125MHz does NOT improve battery life. In fact, many people noticed worse battery life, instability and worse responsiveness,
# Nokia [http://talk.maemo.org/showpost.php?p=601691&postcount=1823 locks the device to 600MHz] during phone calls. This may be a bug. It also [http://talk.maemo.org/showpost.php?p=600721&postcount=1720 affects] Lehto's kernels.
# the telephone app is closed-source and broken. After a phone call it sets the maximum to 600Mhz and the minimum to 250MHz (or  125MHz if available) irrespective of what you have set before. The are some workarounds in the Kernel-power kernel.
# when connected via USB the device locks the minimum frequency to 500Mhz.
# By default the device is configured to use 125MHz as the lowest frequency but it not enabled in the kernel [https://bugs.maemo.org/show_bug.cgi?id=7116 pmconfig bug]
# [http://talk.maemo.org/showpost.php?p=599870&postcount=170 improving responsiveness]
# [http://talk.maemo.org/showpost.php?p=599618&postcount=168 safe pmconfig configuration]
# the warning <pre>WARNING: at arch/arm/mach-omap2/clock34xx.c:443 omap3_noncore_dpll_set_rate+0x28c/0x2dc()</pre> in the kernel logs (dmesg) only happens if the invalid 800MHz frequency was selected. ignore it.
# [http://talk.maemo.org/showpost.php?p=603585&postcount=189 saving more battery power when idle]
# EvilJazz had photoshopped a [http://talk.maemo.org/showpost.php?p=605523&postcount=90 picture of a device being overclocked 1.7GHz]. It's a '''prank'''!
# reading one of the temperature sensors "cat /sys/devices/platform/omap34xx_temp/temp1_input"

==Useful stuff==

===Show current CPU frequency===

awk '{print $1/1000" MHz"}' /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq

'''Important: this command may cause the CPU to bump up to its highest allowed frequency (in other words, you are likely to only see the highest frequency reported when checking this way).'''

===Set maximum CPU frequency===

From root terminal:

echo "echo 600000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq" | root

Replace 600000 with desired maximum frequency. Pay attention to the two exceptions in titan's kernels (124999 and 599000). The list of available frequencies on your device/kernel can be obtained with command:

awk '{print $1/1000" MHz"}' /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state

===Script for analyzing time_in_state (by rooted) - rev7===

''I've stopped the development of this script and I hope someone will make use of the code. I hope titan includes it in "kernel-config show" or "kernel-config debug". -rooted''

This script prints percentage of frequencies (states) used and some additional info useful for posting on the forum (debugging). It displays all frequencies, works with all kernels and it is not affected by the bug which resets minimum frequency after phone call.

Temperature may not be listed if you don't have module bq27x00_battery installed or enabled. Also kernel-power version is not listed if you don't use titan's kernel.

<source lang="bash">
#!/bin/sh

idlefreq=`awk '{if ($2 > 0) print $1}' /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state | tail -n 1`
tis1=`awk '{sum += $2} END {print sum}' /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state`
tis2=`awk '$1 == "'"$idlefreq"'" {idle = $2} {sum += $2} END {print sum-idle}' /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state`

echo -e "
TIME_IN_STATE ANALYSING SCRIPT
By rooted (maemo.org)
Revision 7
wiki.maemo.org/Overclocking

FREQUENCY\tUSED\t\tWHEN BUSY\n"
awk '
{if ($1 >= 1000000)                 printf ("%.0f MHz\t",$1/1000); else printf ("%.0f MHz\t\t",$1/1000)}
{if ($2 == 0)                       printf "unused";               else printf ("%.1f %\t\t",($2*100)/"'"$tis1"'")}
{if ($2 == 0 || $2/"'"$tis2"'" > 1) printf "\n";                   else printf ("%.1f %\n",($2*100)/"'"$tis2"'")}
' /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state

echo -e "
Kernel:                  `uname -r`
kernel-power:            `dpkg -l kernel-power | awk '$2 == "kernel-power" {print $3}'`
kernel-power-settings:   `dpkg -l kernel-power-settings | awk '$2 == "kernel-power-settings" {print $3}'`
Uptime:                  `uptime | sed -e 's/.*p *//' -e 's/, l.*//' -e 's/  / /'`
Load:                    `uptime | sed 's/.*e: //'`
Boot reason:             `cat /proc/bootreason`
Temperature:             `cat /sys/class/power_supply/bq27200-0/temp` degrees C\n"
</source>

Output example:

<pre>TIME_IN_STATE ANALYSING SCRIPT
By rooted (maemo.org)
Revision 7
wiki.maemo.org/Overclocking

FREQUENCY       USED            WHEN BUSY

1150 MHz        unused
1100 MHz        unused
1000 MHz        unused
950 MHz         unused
900 MHz         unused
850 MHz         unused
805 MHz         4.5 %           58.9 %
750 MHz         0.0 %           0.4 %
700 MHz         0.0 %           0.3 %
600 MHz         0.3 %           3.4 %
550 MHz         0.0 %           0.5 %
500 MHz         2.8 %           36.5 %
250 MHz         92.4 %
125 MHz         unused

Kernel:                  2.6.28.10power37
kernel-power:            2.6.28-maemo37
kernel-power-settings:   0.11
Uptime:                  56 min
Load:                    0.25, 0.12, 0.09
Boot reason:             pwr_key
Temperature:             31 degrees C</pre>

===Analyzing time in state, including idle mode stats (by ArbitRabbit)===

The following script will show the current frequency and statistics for each state, including time spent in idle mode when the CPU is actually sleeping. This script works with the special frequency handling in Titan's kernel.

To run this script as user and be able to set the frequencies you will need to install "[[Root_access|rootsh]]" via apt-get.

'''scheduler_stats.sh'''
<source lang="bash">
#!/bin/sh
awk '{print "\nCurrent frequency: "$1/1000" MHz\n"}' /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
awk '{print "Minimum frequency: "$1/1000" MHz\n"}' /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
awk '{print "Maximum frequency: "$1/1000" MHz\n"}' /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq

tis1=`awk '{SUM += $2} END {printf("%.0f",SUM/1000)}' /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state`

idle0=`awk '{printf ("%.0f",$1/1000)}' /sys/devices/system/cpu/cpu0/cpuidle/state0/time`

idle1=`awk '{printf ("%.0f",$1/1000)}' /sys/devices/system/cpu/cpu0/cpuidle/state1/time`

idle2=`awk '{printf ("%.0f",$1/1000)}' /sys/devices/system/cpu/cpu0/cpuidle/state2/time`

idle3=`awk '{printf ("%.0f",$1/1000)}' /sys/devices/system/cpu/cpu0/cpuidle/state3/time`

totaltime=$(($idle0+$idle1+$idle2+$idle3+$tis1))
echo -e "FREQUENCY\tUSED"
SUM=0
awk '
       {
               printf (($1/1000)" MHz \t");
               if ($2 == 0)
               {
                       printf "0 %\n";
               }
               else {
                       SUM+=$2;
                       printf("%.3f %\n",($2/10)/"'"$totaltime"'");
                       }
       }
       END{
       printf ("Time spent in idle mode is %2.2f %\n",(1-((SUM/1000)/"'"$totaltime"'"))*100);
       }' /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state
echo ""
</source>

'''Sample Output'''

<pre>Current frequency: 500 MHz

Minimum frequency: 500 MHz

Maximum frequency: 810 MHz

FREQUENCY       USED
1200 MHz        0 %
1100 MHz        0 %
1000 MHz        0 %
950 MHz         0 %
900 MHz         0 %
850 MHz         0 %
810 MHz         0.000 %
750 MHz         0.000 %
700 MHz         0.000 %
600 MHz         0.000 %
550 MHz         0.000 %
500 MHz         0.010 %
Time spent in idle mode is 99.99 %</pre>

Known Bugs: Requires the Phone to be booted for an hour or so before it results in decent stats.

===Combined helper script (by evilJazz)===

The following script will show the current frequency and statistics. It also accepts two optional parameters that will set the max and/or min frequencies (in MHz unit). Calling the script without these parameters will not set the new clocking. Instead it will just show the current frequencies and statistics.

This script works with the special frequency handling in Titan's kernel.

To run this script as user and be able to set the frequencies you will need to install "[[Root_access|rootsh]]" via apt-get.

overclock.sh [max freq] [min freq]

<source lang="bash">
#!/bin/sh
max=${1}000
min=${2}000

# Handle and rewrite special cases in Titan's kernel...
[ "$max" == "600000" ] && max=599000
[ "$min" == "125000" ] && min=124999

if [ $(id -u) -ne 0 ]; then
  [ "$max" != "000" ] && echo "echo $max > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq" | sudo gainroot
  [ "$min" != "000" ] && echo "echo $min > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq" | sudo gainroot
else
  [ "$max" != "000" ] && echo $max > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
  [ "$min" != "000" ] && echo $min > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
fi

awk '{printf("\nCurrent frequency: %7s MHz\n", $1/1000)}' /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
awk '{printf("Minimal frequency: %7s MHz\n", $1/1000)}' /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
awk '{printf("Maximal frequency: %7s MHz\n\n", $1/1000)}' /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq

sum=$(awk '{SUM += $2} END {print SUM}' /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state)
awk '{printf("%7s MHz: %5.1f % (%8d)\n", ($1/1000), ($2 * 100)/"'"$sum"'", $2)}' /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state
echo
</source>

Output example:

<pre>~ $ ./overclock.sh 600 250

Current frequency:     250 MHz
Minimal frequency:     250 MHz
Maximal frequency:     599 MHz

1200 MHz:   0.0 % (       0)
   1100 MHz:   0.0 % (       0)
   1000 MHz:   0.0 % (       0)
    950 MHz:   0.0 % (       0)
    900 MHz:   0.2 % (     271)
    850 MHz:   0.0 % (       0)
    810 MHz:   0.0 % (       0)
    750 MHz:   0.0 % (       0)
    700 MHz:   0.0 % (       0)
    600 MHz:   9.0 % (   13663)
    550 MHz:   0.5 % (     701)
    500 MHz:  15.4 % (   23379)
    250 MHz:  75.0 % (  114021)
124.999 MHz:   0.0 % (       0)</pre>

===Underclock/Overclock when phone is Locked/Unlocked  (by Fecn)===

When locked, the limits are changed to 250/500Mhz to save power - I don't need my phone to be fast when it's sitting there doing nothing. (I did try with 125Mhz as minimum but it caused an unresponsive touchscreen during incoming phone calls and alarms)

When unlocked, the limits are set for overclocking, with the max speed determined by the temperature ( 1150Mhz is stable on my phone - your mileage may vary - adjust scripts as required)

You need the dbus-scripts package installed for this to work. You also need to add bq27x00_battery to your /etc/modules so that it is loaded at boot time - it needs to be loaded to be able to read the temperature.

We use the dbus-signalling to follow what the phone is doing and fire off scripts to change the limits accordingly.

Create the following two 1-line files inside /etc/dbus-scripts.d/

<pre>
Filename: /etc/dbus-scripts.d/locked 
/usr/local/bin/underclock * * com.nokia.mce.signal tklock_mode_ind locked

Filename: /etc/dbus-scripts.d/unlocked
/usr/local/bin/overclock * * com.nokia.mce.signal tklock_mode_ind unlocked
</pre>

... and then create corresponding scripts that they call inside /usr/local/bin/ ( don't forget to chmod them to executable )

<pre>
Filename: /usr/local/bin/underclock 
#!/bin/sh
kernel-config limits 250 500

Filename: /usr/local/bin/overclock  
#!/bin/sh
TEMP=`cat /sys/class/power_supply/bq27200-0/temp`
echo "Temp is :" $TEMP "C"
MAXSPEED="1150"
if [ $TEMP -gt "38" ] ; then MAXSPEED="1000" ; fi
if [ $TEMP -gt "40" ] ; then MAXSPEED="950" ; fi
if [ $TEMP -gt "43" ] ; then MAXSPEED="850" ; fi
if [ $TEMP -gt "45" ] ; then MAXSPEED="750" ; fi
if [ $TEMP -gt "47" ] ; then MAXSPEED="600" ; fi
echo "Setting max as :" $MAXSPEED "Mhz"

kernel-config limits 250 $MAXSPEED
</pre>

You'll need to restart dbus-scripts for it to see the new configs. I found that the scripts in init.d weren't too good at doing this, so had to kill it manually each time.

If you want to scale your processor speed according to battery capacity in addition to temperature, use an overclock script something like the following:

<pre>
Filename: /usr/local/bin/overclock
#!/bin/sh
TEMP=`cat /sys/class/power_supply/bq27200-0/temp`
echo "Temp is:" $TEMP "C"
MAXSPEED="1150"
if [ $TEMP -gt "38" ] ; then MAXSPEED="1000" ; fi
if [ $TEMP -gt "40" ] ; then MAXSPEED="950" ; fi
if [ $TEMP -gt "43" ] ; then MAXSPEED="850" ; fi
if [ $TEMP -gt "45" ] ; then MAXSPEED="750" ; fi
if [ $TEMP -gt "47" ] ; then MAXSPEED="600" ; fi

BATTERY=`cat /sys/class/power_supply/bq27200-0/capacity`
echo "Battery is:" $BATTERY "% full"
MAXSPEEDTWO="1150"
if [ $BATTERY -lt "60" ] ; then MAXSPEEDTWO="850" ; fi
if [ $BATTERY -lt "40" ] ; then MAXSPEEDTWO="600" ; fi
if [ $BATTERY -lt "25" ] ; then MAXSPEEDTWO="500" ; fi

if [ $MAXSPEEDTWO -lt $MAXSPEED ] ; then MAXSPEED=$MAXSPEEDTWO ; fi

echo "Setting max as:" $MAXSPEED "Mhz"

kernel-config limits 250 $MAXSPEED
</pre>

==Changing the Kernel==

===Installing a modified Kernel===

====Flashing using PC====

# Power off the N900 completely.
# Hold "u" on the N900's keyboard, while holding, connect it to the PC via USB cable.
# You will see usb icon on top right of white Nokia screen.
# Now you can let go of "u" on the keyboard.
# Now use flasher utility with the kernel file located in the same directory.<pre>flasher-3.5 -k image_file_name -f -R</pre>
# It should take about 1-2 seconds then it'll say Done.
# Now your N900 will show white Nokia screen. (reboot)
# At this time, you can pull out the USB cable.
# N900 should finish booting up if all goes well.
# Test out your phone as usual. (Apps, browser, camera, phone etc etc)
# If any abnormal events occur frequently (crash, hang, screen corruption etc), turn it off, flash it to a slower kernel and test again.
note: For Windows7 64bit users, you may need to use WindowsXP mode. ([http://www.youtube.com/watch?v=Bx6dblXl2eo Youtube Tutorial])

====Flashing from N900 xterminal====

* do a backup, have a pc nearby and know you are able to flash the n900 with flasher-3.5 - just in case

# Launch xterminal app then type sudo gainroot (need rootsh installed)
# type:<pre>softupd -vv -s --local</pre>(that is a double v)
# open new terminal
# type:<pre>flasher --local -f -k <kernel_zimage_file_with_path></pre>
# you see the flashing (takes some time)
# type "sync" to save changes
# type "reboot" and enter to restart
# Test out your phone as usual. (Apps, browser, camera, phone etc etc)
# If any abnormal events occur frequently (crash, hang, screen corruption etc), turn it off, flash it to a slower kernel and test again.

'''You are fully responsible for any damage caused by overclocking. Not anyone else.'''

===Reverting to the Original Kernel===

If you want to revert to the original kernel, execute:

apt-get install --reinstall kernel kernel-flasher

=== Fixing the version information ===

If your version information got lost (control panel -> version) you can fix it by reinstalling the package that is listed with:
 dpkg -l "mp-fremantle*"
for example, "mp-fremantle-generic-pr" (for some firmwares 002 or 003 instead of generic) and then execute:
 apt-get install --reinstall mp-fremantle-generic-pr

==Undervolting and voltage tables==

See: http://talk.maemo.org/showpost.php?p=628839&postcount=81

Extract from the post:

<code>CPU power consumption (without constants) = leakage + capacitance + switching = voltage^2 + frequency + (voltage^2 * frequency)</code>

One factor reducing CPU lifetime is the current it is running with.

<code>CPU dynamic power consumption = capacitance * frequency * voltage^2</code> ([[:wikipedia:Dynamic_frequency_scaling]])

As can be seen from the formula lower voltage plays greater part in CPU consumption than frequency. By reducing the voltage the damage of overclocking can be reduced and the battery life time extended.

===Calculating voltages===

According to [http://talk.maemo.org/showpost.php?p=606031&postcount=2375 this calculations] the voltage can be varied in steps of 0.0125 V with values 0-72. The formula is (with x being the kernel parameter value):

Examples:

Lowest voltage (x = 0):   0  * 0.0125 + 0.6 = 0     + 0.6 = 0.6 V
 Highest voltage (x = 72): 72 * 0.0125 + 0.6 = 0.9   + 0.6 = 1.5 V
 Random voltage (x = 38):  38 * 0.0125 + 0.6 = 0.475 + 0.6 = 1.075 V

===Summary===

FREQUENCY   Nokia   LV    ULV   XLV   ideal
 0 MHz       30      30    25    30    30
 125 MHz     30      30    25    20    30
 250 MHz     38      38    25    30    30
 500 MHz     48      48    33    33    30
 550 MHz    *54*     48    38    38    33
 600 MHz     60     *54*   38    38    38
 700 MHz             54    45    45    45
 750 MHz             54    45    45    45
 810 MHz             54    48    48    48
 850 MHz             54    48    48    48
 900 MHz             54   *54*  *54*  *54*
 950 MHz             54    54    54    54
 1000 MHz            60    60    60    60
 1100 MHz            72    72    72    72
 1150 MHz            72    72    72    72

Note: Asterisks indicate the first frequency in the kernel which needs overvoltage.

===/sys/power/vdd1_opps_vsel values===

LV:      "30 30 38 48 48 54 54 54 54 54 54 54 60 72 72"
 ULV:     "25 25 25 33 38 38 45 45 48 48 54 54 60 72 72"
 XLV:     "30 20 30 33 38 38 45 45 48 48 54 54 60 72 72"
 ideal:   "30 30 30 30 33 38 45 45 48 48 54 54 60 72 72"

===Kernels' specifications===

====Nokia's kernel====

VALUE  VOLTAGE   FREQUENCY     DYNAMIC POWER
 30     0.975 V   0 MHz         0.000 V²/us
 30     0.975 V   125 MHz       118.828 V²/us
 38     1.075 V   250 MHz       288.906 V²/us
 48     1.200 V   500 MHz       720.000 V²/us
 54     1.275 V   550 MHz       894.094 V²/us
 60     1.350 V   600 MHz       1093.500 V²/us

====titan's LV kernel====

VALUE  VOLTAGE   FREQUENCY     DYNAMIC POWER
 30     0.975V    0 MHz         0.000 V²/us
 30     0.975V    125 MHz       118.828 V²/us
 38     1.075V    250 MHz       288.906 V²/us
 48     1.200V    500 MHz       720.000 V²/us
 48     1.200V    550 MHz       792.000 V²/us
 54     1.275V    600 MHz       975.375 V²/us
 54     1.275V    700 MHz       1137.938 V²/us
 54     1.275V    750 MHz       1219.219 V²/us
 54     1.275V    810 MHz       1316.756 V²/us
 54     1.275V    850 MHz       1381.781 V²/us
 54     1.275V    900 MHz       1463.062 V²/us
 54     1.275V    950 MHz       1544.344 V²/us
 60     1.350V    1000 MHz      1822.500 V²/us
 72     1.500V    1100 MHz      2475.000 V²/us
 72     1.500V    1200 MHz      2700.000 V²/us

====titan's ULV kernel====

VALUE  VOLTAGE   FREQUENCY    DYNAMIC POWER
 25     0.912V    0 MHz        0.000 V²/us
 25     0.912V    125 MHz      103.968 V²/us
 25     0.912V    250 MHz      207.936 V²/us
 33     1.012V    500 MHz      512.072 V²/us
 38     1.075V    550 MHz      635.594 V²/us
 38     1.075V    600 MHz      693.375 V²/us
 45     1.163V    700 MHz      946.798 V²/us
 45     1.163V    750 MHz      1014.427 V²/us
 48     1.200V    810 MHz      1166.400 V²/us
 48     1.200V    850 MHz      1224.000 V²/us
 54     1.275V    900 MHz      1463.062 V²/us
 54     1.275V    950 MHz      1544.344 V²/us
 60     1.350V    1000 MHz     1822.500 V²/us
 72     1.500V    1100 MHz     2475.000 V²/us
 72     1.500V    1200 MHz     2700.000 V²/us

====titan's XLV kernel====

VALUE  VOLTAGE   FREQUENCY    DYNAMIC POWER
 30     0.975V    0 MHz        0.000 V²/us
 20     0.850V    125 MHz      90.312 V²/us
 30     0.975V    250 MHz      237.656 V²/us
 33     1.012V    500 MHz      512.072 V²/us
 38     1.075V    550 MHz      635.594 V²/us
 38     1.075V    600 MHz      693.375 V²/us
 45     1.163V    700 MHz      946.798 V²/us
 45     1.163V    750 MHz      1014.427 V²/us
 48     1.200V    810 MHz      1166.400 V²/us
 48     1.200V    850 MHz      1224.000 V²/us
 54     1.275V    900 MHz      1463.062 V²/us
 54     1.275V    950 MHz      1544.344 V²/us
 60     1.350V    1000 MHz     1822.500 V²/us
 72     1.500V    1100 MHz     2475.000 V²/us
 72     1.500V    1150 MHz     2587.500 V²/us

====titan's ideal kernel====

VALUE  VOLTAGE   FREQUENCY    DYNAMIC POWER
 30     0.975V    0 MHz        0.000 V²/us
 30     0.975V    125 MHz      118.828 V²/us
 30     0.975V    250 MHz      237.656 V²/us
 30     0.975V    500 MHz      475.312 V²/us
 33     1.012V    550 MHz      563.279 V²/us
 38     1.075V    600 MHz      693.375 V²/us
 45     1.163V    700 MHz      946.798 V²/us
 45     1.163V    750 MHz      1014.427 V²/us
 48     1.200V    810 MHz      1166.400 V²/us
 48     1.200V    850 MHz      1224.000 V²/us
 54     1.275V    900 MHz      1463.062 V²/us
 54     1.275V    950 MHz      1544.344 V²/us
 60     1.350V    1000 MHz     1822.500 V²/us
 72     1.500V    1100 MHz     2475.000 V²/us
 72     1.500V    1150 MHz     2587.500 V²/us

[[Category:Power users]]

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-==Reminders==
+==Overclocking==
-This page is about overclocking and undervolting the [[Nokia N900|N900]]. For the N8x0 see [http://talk.maemo.org/showthread.php?t=12464 this thread on talk.maemo.org]
+This page is about overclocking the [[Nokia N900|N900]]. For the N8x0 see [http://talk.maemo.org/showthread.php?t=12464 this thread on talk.maemo.org]
-Overclocking is discussed in [http://talk.maemo.org/showthread.php?t=39753 this thread]. Benchmark results can be found [http://talk.maemo.org/showthread.php?p=605189 here]. If you're more interested in power saving read [http://talk.maemo.org/showthread.php?t=49654 this].
+&#x23; ''WORK IN PROGRESS, HELP IF YOU WANT''
-This guide focuses on kernel-power v50 and above, as it introduces improvements in stability and maximum supported frequency for SmartReflex, making it highly desirable for a Maemo system that is overclocked 24/7.
+Overclocking is discussed in [http://talk.maemo.org/showthread.php?t=39753 this thread].
+Benchmark results can be found [http://talk.maemo.org/showthread.php?p=605189 here].
+If you're more interested in power saving read [http://talk.maemo.org/showthread.php?t=49654 this].
 ==Warnings==
 * Overclocking WILL VOID YOUR WARRANTY. Your warranty does not cover running the device beyond the specifications.
-* The lifetime of your device WILL get reduced as a result of [[:wikipedia:Electromigration]]
+* The lifetime of your device may get reduced (see below)
-* Your device might not perform properly - bizarre bugs and corruption may result from the CPU being physically unable to cope with higher frequencies (see the next point)
+* Your data might get corrupted (for example, file system corruption)
-* All devices are not made equal - some may be able to handle 1.15GHz daily just fine, while some may be unstable even at 720MHz.
+* Every device is an individual, what is stable for others might not be for you
+* If you encounter ANY unusual problems, lower your clock frequency
 * You do it at your own responsibility. No whining afterwards. If you're unsure, don't do it.
-* Nokia's overclocking warning: 500 MHz is the normal frequency. Everything above is not good for your device, even with the stock kernel.
+* [http://depot.javispedro.com/nit/thewarningtm.jpeg Nokia's overclocking warning]: 500MHz is the normal frequency. Everything above is not good for your device, even with the stock kernel.
 * Igor Stoppa's [http://talk.maemo.org/showpost.php?p=596149&postcount=904 warning] and [http://talk.maemo.org/showpost.php?p=603833&postcount=66 comment]
 * [http://talk.maemo.org/showpost.php?p=596274&postcount=937 chip vendors specs]
@@ Line 23: / Line 26: @@
 * It is usually much longer (several years) than the warranty period, so that even with heavy use within the specifications it would not fail before warranty ends.
 * With overclocking users may see considerable speed improvements and lower latency in user experience which could extend the actual lifetime (of being used) as the device could keep up with the newer models.
-* Excessive overclocking with stock voltages is definitely bad for most components in your device, especially if the device is continuously locked at high frequencies with high load (see TI specs).
+* Naive overclocking with stock voltages is definitely bad for most components in your device, especially if the device is continuously locked at high frequencies with high load (see TI specs).
 * Specifications give guarantees for the worst-case scenarios that are covered by the warranty. The best-case scenario may be different for every device but is not covered by warranty.
-* However, there is an open debate whether '''mild''' (<40%) overclocking with lower voltages (undervolting) does actually harm or is even less harmful than the stock settings. See [[#Undervolting and voltage tables]] for an explanation why undervolting in fact won't help anything due to chip using SmartReflex Technology (which can not be disabled).
+* However, there is an open debate whether '''mild''' (<40%) overclocking with lower voltages (undervolting) does actually harm or is even less harmful than the stock settings.
-* Evidence for or against damages (esp. with undervolting) in the N900 is currently absent and will probably only be available when the device is no longer on the market. Or you decide to acquire thorough electronics engineer's understanding of the issue, and study TI's papers regarding SmartReflex™ and how it works - then all the evidence for damage positively done is there already.
+* Evidence for or against damages (esp. with undervolting) in the N900 is currently absent and will probably only be available when the device is no longer on the market.
 * Therefore, if you are unsure and you want to avoid potential damages, do not overclock!
 ==Overclocking, bugzilla & errors==
-* Running a device overclocked for long periods of time could produce unwanted side effects, even persisting ones that won't revert when overclocking is stopped. If you are experiencing errors following overclocking and intend to report those errors to talk.maemo.org or bugzilla, please consider the following :
+* Running a device overclocked for long periods of time could produce unwanted side effects. If you are expiriencing errors following Overclocking and intend to report those errors to talk.maemo.org or bugzilla, please consider the following :
-** Errors induced by overclocking will not always appear to be as such.
+**Errors induced by overclocking will not always appear to be as such.
-** It will be considered a good idea to reproduce your error / problem on a device which has never been overclocked AT ALL, before proceeding with actions regarding your problem.
+**It will be considered a good idea to reproduce your error / problem on a device which has not been overclocked AT ALL before proceeding with actions regarding your problem.
-** In the event you have decided to file a bug report or open a thread about your problem, please add a note to that report, mentioning that you are or previously were in fact running your device overclocked.  Please also provide details about the period and amount of overclocking used.
+**In the event you have decided to file a bug report or open a thread about your problem, please add a note to that report, mentioning that you are infact running your device overclocked.  Please also provide details about the period and amount of overclocking used.
-* The reason for these requirements is that there are many problems pending for developer's attention. It is a huge waste of time to try and trace down an error without knowing all the facts, just to find out in the end that the particular problem was caused by a damaged hardware. If the developers know about it, they can take it into account and won't rule out a 1+1=3 problem on the reporter's device during their analysis.
+*The reason for these requirements is that there many problems pending for developer's attention. The priority is to work on problems not related to overclocking, since the majority of users are not overclocking their devices.
-==Additional information and hints==
+==Available kernels==
-* The stock Nokia kernel uses the following frequencies: 250, 500, 550 and 600 MHz.
+Overclocking requires installation of a custom kernel. There are two types of kernels:
-* The CPU does '''NOT IDLE''' at the lowest frequency (250 MHz) but it '''SLEEPS''' at 0 MHz! Thus, reducing the lowest frequency would not reduce power consumption. It is only activated during low workload and may actually consume more power than a higher frequency, as it takes more time to go back to sleep/idle state.
+# modified PR1.1 kernels by Lehto and others. The only difference from the stock Nokia kernel is the change of the available hardcoded frequencies.
-* Setting the lowest frequency to 125 MHz does NOT improve battery life. In fact, many people noticed worse battery life, instability and worse responsiveness,
+# enhanced kernels by titan. They are compatible with PR1.2 (!), contain lots of additional features (IPv6, NAT etc) and bugfixes. In addition they include a large set of possible frequencies (125MHz-1.15GHz) which you manually set and try out without flashing a new kernel. The defaults are set to the standard 250-600MHz range. The kernel can be installed via HAM from the [[extras-devel]] catalog.
-* The Phone app is closed-source and broken. During a phone call, the device's frequency [http://talk.maemo.org/showpost.php?p=601691&postcount=1823 is locked to 600MHz]. This may be a bug, and it affects all kernels for Fremantle. After a phone call, it sets the maximum to 600 Mhz and the minimum to 250 MHz (or 125 MHz if available) regardless of the frequencies you have set. There are some workarounds present in kernel-power, however the bug may still occasionally manifest.
-* When connected via USB the device locks the minimum frequency to 500 Mhz.
-* By default the device is configured to use 125 MHz as the lowest frequency but it not enabled in the kernel [https://bugs.maemo.org/show_bug.cgi?id=7116 pmconfig bug]
-* The warning <pre>WARNING: at arch/arm/mach-omap2/clock34xx.c:443 omap3_noncore_dpll_set_rate+0x28c/0x2dc()</pre> in the kernel logs (dmesg) only happens if the invalid 800 MHz frequency was selected. Ignore it.
-* EvilJazz had photoshopped a [http://talk.maemo.org/showpost.php?p=605523&postcount=90 picture of a device being overclocked 1.7GHz]. It's a '''prank'''!
-* The internal temperature sensor may be read by using the command "cat /sys/devices/platform/omap34xx_temp/temp1_input"
-* '''Note''' that the system does not have an on-die temperature sensor, and the actual CPU temperature may be higher or lower than the reading.
-==Installing a modified kernel==
+=== Jakiman's Guide to Overclocking for Newcomers ===
-Overclocking and undervolting require installation of a custom kernel.
-There are two types of kernels:
-===Kernel-Power (recommended)===
+[http://talk.maemo.org/showpost.php?p=595582&postcount=774 Jakiman's Overclock Guide / Summary] (constantly updated)
-[[Kernel_Power|kernel-power]], developed by Titan and maintained by Pali.
-They are compatible with [[Maemo 5/PR1.2|PR1.2]] and [[Maemo 5/PR1.3|PR1.3]], contain lots of additional features (IPv6, NAT etc) and bugfixes. In addition, they include a large set of possible frequencies (125 MHz-1.15 GHz) which can be manually set and tested without flashing a new kernel.
-The defaults are set to the standard 250-600 MHz range.
+=== Installation of Lehto's PR1.1 kernels ===
-This guide recommends using kernel-power v50, which at the time of writing is available in the [[extras]] catalog. Newer, more experimental kernels may be available through [[extras-testing]] or [[extras-devel]].
+[http://talk.maemo.org/showpost.php?p=594200&postcount=309 Lehto's Kernels]
-====Installing from the repositories====
+=== Installation of titan's enhanced kernels ===
-# Open the Application Manager
-# Go to the "System" section, and install the package kernel-power-settings. This automatically pulls in the rest of kernel-power as dependencies.
-# After successful installation, reboot the device.
-===Lehto's Kernel and other legacy kernels===
+This kernel makes it possible to dynamically change the maximum frequency up to 1.15GHz (supported frequencies are 125,250,500,550,600,700,750,805,850,900,950,1000,1100,1150MHz).
-Modified [[Maemo 5/PR1.1|PR1.1]] kernels by Lehto and others. The only difference from the stock Nokia kernel is the change of the available hardcoded frequencies.
-====Flashing from X Terminal====
+see the separate page for this kernel: [[Kernel_Power]]
-* do a backup, have a PC nearby and know you are able to flash the N900 with flasher-3.5 - just in case
-# Launch X Terminal, then type<pre>sudo gainroot</pre>
+[http://talk.maemo.org/showthread.php?t=43420 talk.maemo.org: Discussion of the enhanced kernel]
-# Type:<pre>softupd -vv -s --local</pre>(that is a double v)
-# Open new terminal
-# Type:<pre>flasher --local -f -k <kernel_zimage_file_with_path></pre>
-# You'll see the flashing (takes some time)
-# Type "sync" to save changes
-# Type "reboot" and enter to restart
-# Test out your phone as usual. (Apps, browser, camera, phone etc etc)
-# If any abnormal events occur frequently (crash, hang, screen corruption etc), turn it off, flash it to a slower kernel and test again.
-===Reverting to the Stock Kernel===
+==Additional information and hints==
-If you want to revert to the stock Nokia kernel, execute:
+# the frequencies available in the Nokia kernel are: 250, 500, 550 and 600MHz.
+# the CPU does '''NOT IDLE''' at the lowest frequency (250MHz) but it '''SLEEPS''' at 0MHz! Thus reducing the lowest frequency would not reduce power consumption. It is only activated during low workload and may actually consume more power than a higher frequency, as it takes more time to go back to sleep/idle state.
+# setting the lowest frequency to 125MHz does NOT improve battery life. In fact, many people noticed worse battery life, instability and worse responsiveness,
+# Nokia [http://talk.maemo.org/showpost.php?p=601691&postcount=1823 locks the device to 600MHz] during phone calls. This may be a bug. It also [http://talk.maemo.org/showpost.php?p=600721&postcount=1720 affects] Lehto's kernels.
+# the telephone app is closed-source and broken. After a phone call it sets the maximum to 600Mhz and the minimum to 250MHz (or  125MHz if available) irrespective of what you have set before. The are some workarounds in the Kernel-power kernel.
+# when connected via USB the device locks the minimum frequency to 500Mhz.
+# By default the device is configured to use 125MHz as the lowest frequency but it not enabled in the kernel [https://bugs.maemo.org/show_bug.cgi?id=7116 pmconfig bug]
+# [http://talk.maemo.org/showpost.php?p=599870&postcount=170 improving responsiveness]
+# [http://talk.maemo.org/showpost.php?p=599618&postcount=168 safe pmconfig configuration]
+# the warning <pre>WARNING: at arch/arm/mach-omap2/clock34xx.c:443 omap3_noncore_dpll_set_rate+0x28c/0x2dc()</pre> in the kernel logs (dmesg) only happens if the invalid 800MHz frequency was selected. ignore it.
+# [http://talk.maemo.org/showpost.php?p=603585&postcount=189 saving more battery power when idle]
+# EvilJazz had photoshopped a [http://talk.maemo.org/showpost.php?p=605523&postcount=90 picture of a device being overclocked 1.7GHz]. It's a '''prank'''!
+# reading one of the temperature sensors "cat /sys/devices/platform/omap34xx_temp/temp1_input"
- apt-get install --reinstall kernel kernel-flasher
+==Useful stuff==
-in X Terminal.
+===Show current CPU frequency===
-=== Fixing the version information ===
+ awk '{print $1/1000" MHz"}' /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
-If your version information got lost (control panel -> version) you can fix it by reinstalling the package that is listed with:
+'''Important: this command may cause the CPU to bump up to its highest allowed frequency (in other words, you are likely to only see the highest frequency reported when checking this way).'''
- dpkg -l "mp-fremantle*"
-for example, "mp-fremantle-generic-pr" (for some firmwares 002 or 003 instead of generic) and then execute:
- apt-get install --reinstall mp-fremantle-generic-pr
-==Overclocking==
+===Set maximum CPU frequency===
-Once you have installed kernel-power, you are ready to start overclocking.
-# List available frequencies ("active frequencies")<pre> sudo kernel-config show </pre>
-# Select the lowest and highest frequencies to be used from the list of active frequencies,  The kernel will use all '''active frequencies''' between and including those you selected.
-# The following command will set the frequencies to stock:<pre> sudo kernel-config limits 250 600 </pre>
-# The following command will set the maximum to the highest supported by '''SmartReflex'''. (Note that SmartReflex in kernel-power v50 only works with frequencies up to 900MHz.)<pre> sudo kernel-config limits 250 900 </pre>
-# At this point, you should test system stability by launching a few programs, browsing JavaScript-heavy webpages, and playing a movie.
-# Should you encounter no reboots, you can save your overclocking profile.<pre> sudo kernel-config save myprofile </pre>
-# You can now proceed to set your kernel profile as the default, to be loaded automatically at startup.<pre> sudo kernel-config default myprofile </pre>
-==Undervolting==
+From root terminal:
-===SmartReflex===
+ echo "echo 600000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq" | root
-====Rationale====
+Replace 600000 with desired maximum frequency. Pay attention to the two exceptions in titan's kernels (124999 and 599000). The list of available frequencies on your device/kernel can be obtained with command:
-Before kernel-power v50, one would normally set voltages per frequency in a configuration file, which required manual testing to determine the lowest voltages possible for a specific frequency. This may result in reboots if the voltage was not set high enough to account for the CPU's power usage at full loads, or power wastage if the voltages were set higher than what is needed for light loads at a certain frequency.
-SmartReflex is a technology which automatically regulates the voltage used for the entire SoC, automatically adapting to lower voltages during light use and increase them during heavy use.
-====Automatic Undervolting====
+ awk '{print $1/1000" MHz"}' /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state
-Once kernel-power v50 or higher is installed, enabling it is a matter of doing the following:
-# Make a folder for your kernel profiles<pre> mkdir -p ~/.kernel </pre>
-# Copy a sane profile to your kernel profile folder<pre> cp /usr/share/kernel-power-settings/default ~/.kernel/myprofile </pre>
-# Edit the profile to enable SmartReflex<pre> nano ~/.kernel/myprofile </pre>
-# Look for the lines:<pre> SMARTREFLEX_VDD1=0 SMARTREFLEX_VDD2=0</pre>
-# Edit them to the following:<pre>SMARTREFLEX_VDD1=1 SMARTREFLEX_VDD2=1</pre>
-# Save the file by pressing Ctrl+X, and confirm with Y then press Enter.
-# Test the profile<pre> sudo kernel-config load myprofile </pre>
-# At this point, you'd want to stress the CPU a bit. Launch a few programs, visit JS-heavy websites, etc.
-# If the device does not reboot and you feel safe using the profile, set it as the default.<pre> sudo kernel-config default myprofile </pre>
-# Congratulations, the kernel is now doing all the work for you.
-===Manual Undervolting (Legacy)===
+===Script for analyzing time_in_state (by rooted) - rev7===
-See: http://talk.maemo.org/showpost.php?p=628839&postcount=81
-Extract from the post:
+''I've stopped the development of this script and I hope someone will make use of the code. I hope titan includes it in "kernel-config show" or "kernel-config debug". -rooted''
-<pre>CPU power consumption (without constants) = leakage + capacitance + switching = voltage^2 + frequency + (voltage^2 * frequency)</pre>
-One factor reducing CPU lifetime is the current it is running with [[:wikipedia:Dynamic_frequency_scaling|dynamic frequency scaling]].
-<pre>CPU dynamic power consumption = capacitance * frequency * voltage^2</pre>
-As can be seen from the formula, lower voltage plays greater part in CPU consumption than frequency. By reducing the voltage the damage of overclocking can be reduced and the battery life time extended. Alas, this claim only holds true for architectures not regulating the real voltage and current in special on chip regulators, like OMAP is known to do for almost every gate in their CPU and other SoC function blocks. TI calls this feature SmartReflex™ and lowering the voltage applied to the whole SoC, like suggested here, only reduces the voltage drop across these regulators, thus no positive effect on [[:wikipedia:Electromigration|electromigration damage]] caused by overclocking is to be expected.
-====Calculating Voltages====
-According to [http://talk.maemo.org/showpost.php?p=606031&postcount=2375 these calculations], the voltage can be varied in steps of 0.0125 V with values 0-72.
-The formula is (with x being the kernel parameter value):
-<pre>V = x * 0.0125 + 0.6</pre>
-Examples:
- Lowest voltage (x = 0):   0  * 0.0125 + 0.6 = 0     + 0.6 = 0.6 V
- Highest voltage (x = 72): 72 * 0.0125 + 0.6 = 0.9   + 0.6 = 1.5 V
- Random voltage (x = 38):  38 * 0.0125 + 0.6 = 0.475 + 0.6 = 1.075 V
-====Voltage Table====
-* V²/us for frequencies 720 and 805 need to be recalculated.
-* Bolded steps indicate the first frequency in the kernel which needs overvoltage. ''All frequencies after it are overvolted''.
-{|
-! Frequency !! Nokia !! LV !! ULV !! XLV !! ideal !! starving
-|-
-|0 MHz || 30 || 30 || 25 || 30 || 30 || 22
-|-
-| || 0.975V, 0.000 V²/us || 0.975V, 0.000 V²/us || 0.912V, 0.000 V²/us || 0.975V, 0.000 V²/us || 0.975V, 0.000 V²/us ||
-|-
-|125 MHz || 30 || 30 || 25 || 20 || 30 || 22
-|-
-| || 0.975V, 288.906 V²/us || 0.975V, 118.828 V²/us || 0.912V, 103.968 V²/us || 0.975V, 118.828 V²/us || 0.975V, 118.828 V²/us ||
-|-
-|250 MHz || 38 || 38 || 25 || 30 || 30 || 28
-|-
-| || 1.075 V, 118.828 V²/us || 1.075 V, 118.828 V²/us || 0.912V, 207.936 V²/us || 0.975V, 237.656 V²/us || 0.975V, 237.656 V²/us ||
-|-
-|500 MHz || 48 || 48 || 33  || 33 || 30 || 29
-|-
-| || 1.200 V, 720.000 V²/us || 1.200 V, 720.000 V²/us || 1.012V, 512.072 V²/us || 1.012V, 512.072 V²/us || 0.975V, 475.312 V²/us ||
-|-
-|550 MHz || '''54''' || 48 || 38 || 38 || 33 || 32
-|-
-| || 1.275 V, 894.094 V²/us || 1.200 V, 792.000 V²/us || 1.075V, 635.594 V²/us || 1.075V, 635.594 V²/us || 1.012V, 563.279 V²/us ||
-|-
-|600 MHz || 60 || '''54''' || 38 || 38 || 38 || 34
-|-
-| || 1.350 V, 1093.500 V²/us || 1.275 V, 975.375 V²/us || 1.075V, 693.375 V²/us || 1.075V, 693.375 V²/us || 1.075V, 693.375 V²/us ||
-|-
-|720 MHz || || 54 || 45 || 45 || 45 || 42
-|-
-| || || 1.275 V, 1137.938 V²/us || 1.163 V, 1014.427 V²/us || 1.163 V, 1014.427 V²/us || 1.163 V, 1014.427 V²/us ||
-|-
-|805 MHz || || 54 || 48 || 48 || 48 || 45
-|-
-| || || 1.275 V, 1316.756 V²/us || 1.200 V, 1166.400 V²/us || 1.200 V, 1166.400 V²/us || 1.200V, 1166.200 V²/us ||
-|-
-|850 MHz || || 54 || 48 || 48 || 48 || 46
-|-
-| || || 1.275 V, 1381.781 V²/us || 1.200 V, 1224.000 V²/us || 1.200 V, 1224.000 V²/us || 1.200V, 1224.000 V²/us ||
-|-
-|900 MHz || || 54 || '''54''' || '''54''' || '''54''' || 49
-|-
-| || || 1.275 V, 1463.062 V²/us || 1.275V, 1463.062 V²/us || 1.275V, 1463.062 V²/us || 1.275 V, 1463.062 V²/us ||
-|-
-|950 MHz || || 54 || 54 || 54 || 54 || 52
-|-
-| || || 1.275 V, 1544.344 V²/us || 1.275 V, 1544.344 V²/us || 1.275 V, 1544.344 V²/us || 1.275 V, 1544.344 V²/us ||
-|-
-|1000 MHz || || 60 || 60 || 60 || 60 || 55
-|-
-| || || 1.350 V, 1822.500 V²/us || 1.350 V, 1822.500 V²/us || 1.350 V, 1822.500 V²/us || 1.350 V, 1822.500 V²/us ||
-|-
-|1100 MHz || || 72 || 72 || 72 || 72 || 63
-|-
-| || || 1.500 V, 2475.000 V²/us || 1.500 V, 2475.000 V²/us || 1.500 V, 2475.000 V²/us || 1.500 V, 2475.000 V²/us ||
-|-
-|1150 MHz || || 72 || 72 || 72 || 72 || 69
-|-
-| || || 1.500 V, 2700.000 V²/us || 1.500 V, 2700.000 V²/us || 1.500 V, 2700.000 V²/us || 1.500 V, 2700.000 V²/us ||
-|}
-==Useful scripts==
-===Analyze kernel system frequency use percentage===
-Written by ''rooted''
-''I've stopped the development of this script and I hope someone will make use of the code. I hope titan includes it in "kernel-config show" or "kernel-config debug". -rooted''
 This script prints percentage of frequencies (states) used and some additional info useful for posting on the forum (debugging). It displays all frequencies, works with all kernels and it is not affected by the bug which resets minimum frequency after phone call.
@@ Line 291: / Line 169: @@
 Temperature:             31 degrees C</pre>
-===Analyze kernel system frequency use percentage, including idle mode stats===
+===Analyzing time in state, including idle mode stats (by ArbitRabbit)===
-Written by ''ArbitRabbit''
 The following script will show the current frequency and statistics for each state, including time spent in idle mode when the CPU is actually sleeping. This script works with the special frequency handling in Titan's kernel.
@@ Line 361: / Line 238: @@
 Known Bugs: Requires the Phone to be booted for an hour or so before it results in decent stats.
-===Combined helper script===
+===Combined helper script (by evilJazz)===
-Written by ''EvilJazz''
 The following script will show the current frequency and statistics. It also accepts two optional parameters that will set the max and/or min frequencies (in MHz unit). Calling the script without these parameters will not set the new clocking. Instead it will just show the current frequencies and statistics.
@@ Line 421: / Line 297: @@
 .999 MHz:   0.0 % (       0)</pre>
-===Underclock/Overclock when phone is locked/unlocked===
+===Underclock/Overclock when phone is Locked/Unlocked  (by Fecn)===
-Written by ''Fecn''
-When locked, the limits are changed to 250/500 Mhz to save power - I don't need my phone to be fast when it's sitting there doing nothing. (I did try with 125 Mhz as minimum but it caused an unresponsive touchscreen during incoming phone calls and alarms)
+When locked, the limits are changed to 250/500Mhz to save power - I don't need my phone to be fast when it's sitting there doing nothing. (I did try with 125Mhz as minimum but it caused an unresponsive touchscreen during incoming phone calls and alarms)
-When unlocked, the limits are set for overclocking, with the max speed determined by the temperature (1150 Mhz is stable on my phone - your mileage may vary - adjust scripts as required)
+When unlocked, the limits are set for overclocking, with the max speed determined by the temperature ( 1150Mhz is stable on my phone - your mileage may vary - adjust scripts as required)
 You need the dbus-scripts package installed for this to work. You also need to add bq27x00_battery to your /etc/modules so that it is loaded at boot time - it needs to be loaded to be able to read the temperature.
-Note by --[[User:joerg_rw|joerg_rw]] 18:03, 2 August 2010 (UTC):
-Which temperature are you trying to base that on? Anyway the bq27200 temperature is vastly useless for this purpose, as it is the die (chip) temperature of the battery charge gauge, and neither related to CPU die temperature, nor to battery cell temperature.
 We use the dbus-signalling to follow what the phone is doing and fire off scripts to change the limits accordingly.
-Create the following two 1-line files inside /etc/dbus-scripts.d/  (before you need to install the dbus-scripts package)
+Create the following two 1-line files inside /etc/dbus-scripts.d/
 <pre>
@@ Line 496: / Line 368: @@
 kernel-config limits 250 $MAXSPEED
 </pre>
+==Changing the Kernel==
+===Installing a modified Kernel===
+====Flashing using PC====
+# Power off the N900 completely.
+# Hold "u" on the N900's keyboard, while holding, connect it to the PC via USB cable.
+# You will see usb icon on top right of white Nokia screen.
+# Now you can let go of "u" on the keyboard.
+# Now use flasher utility with the kernel file located in the same directory.<pre>flasher-3.5 -k image_file_name -f -R</pre>
+# It should take about 1-2 seconds then it'll say Done.
+# Now your N900 will show white Nokia screen. (reboot)
+# At this time, you can pull out the USB cable.
+# N900 should finish booting up if all goes well.
+# Test out your phone as usual. (Apps, browser, camera, phone etc etc)
+# If any abnormal events occur frequently (crash, hang, screen corruption etc), turn it off, flash it to a slower kernel and test again.
+note: For Windows7 64bit users, you may need to use WindowsXP mode. ([http://www.youtube.com/watch?v=Bx6dblXl2eo Youtube Tutorial])
+====Flashing from N900 xterminal====
+* do a backup, have a pc nearby and know you are able to flash the n900 with flasher-3.5 - just in case
+# Launch xterminal app then type sudo gainroot (need rootsh installed)
+# type:<pre>softupd -vv -s --local</pre>(that is a double v)
+# open new terminal
+# type:<pre>flasher --local -f -k <kernel_zimage_file_with_path></pre>
+# you see the flashing (takes some time)
+# type "sync" to save changes
+# type "reboot" and enter to restart
+# Test out your phone as usual. (Apps, browser, camera, phone etc etc)
+# If any abnormal events occur frequently (crash, hang, screen corruption etc), turn it off, flash it to a slower kernel and test again.
+'''You are fully responsible for any damage caused by overclocking. Not anyone else.'''
+===Reverting to the Original Kernel===
+If you want to revert to the original kernel, execute:
+ apt-get install --reinstall kernel kernel-flasher
+=== Fixing the version information ===
+If your version information got lost (control panel -> version) you can fix it by reinstalling the package that is listed with:
+ dpkg -l "mp-fremantle*"
+for example, "mp-fremantle-generic-pr" (for some firmwares 002 or 003 instead of generic) and then execute:
+ apt-get install --reinstall mp-fremantle-generic-pr
+==Undervolting and voltage tables==
+See: http://talk.maemo.org/showpost.php?p=628839&postcount=81
+Extract from the post:
+<code>CPU power consumption (without constants) = leakage + capacitance + switching = voltage^2 + frequency + (voltage^2 * frequency)</code>
+One factor reducing CPU lifetime is the current it is running with.
+<code>CPU dynamic power consumption = capacitance * frequency * voltage^2</code> ([[:wikipedia:Dynamic_frequency_scaling]])
+As can be seen from the formula lower voltage plays greater part in CPU consumption than frequency. By reducing the voltage the damage of overclocking can be reduced and the battery life time extended.
+===Calculating voltages===
+According to [http://talk.maemo.org/showpost.php?p=606031&postcount=2375 this calculations] the voltage can be varied in steps of 0.0125 V with values 0-72. The formula is (with x being the kernel parameter value):
+<code>V = x * 0.0125 + 0.6</code>
+Examples:
+ Lowest voltage (x = 0):   0  * 0.0125 + 0.6 = 0     + 0.6 = 0.6 V
+ Highest voltage (x = 72): 72 * 0.0125 + 0.6 = 0.9   + 0.6 = 1.5 V
+ Random voltage (x = 38):  38 * 0.0125 + 0.6 = 0.475 + 0.6 = 1.075 V
+===Summary===
+ FREQUENCY   Nokia   LV    ULV   XLV   ideal
+MHz       30      30    25    30    30
+MHz     30      30    25    20    30
+MHz     38      38    25    30    30
+MHz     48      48    33    33    30
+MHz    *54*     48    38    38    33
+MHz     60     *54*   38    38    38
+MHz             54    45    45    45
+MHz             54    45    45    45
+MHz             54    48    48    48
+MHz             54    48    48    48
+MHz             54   *54*  *54*  *54*
+MHz             54    54    54    54
+MHz            60    60    60    60
+MHz            72    72    72    72
+MHz            72    72    72    72
+Note: Asterisks indicate the first frequency in the kernel which needs overvoltage.
+===/sys/power/vdd1_opps_vsel values===
+ LV:      "30 30 38 48 48 54 54 54 54 54 54 54 60 72 72"
+ ULV:     "25 25 25 33 38 38 45 45 48 48 54 54 60 72 72"
+ XLV:     "30 20 30 33 38 38 45 45 48 48 54 54 60 72 72"
+ ideal:   "30 30 30 30 33 38 45 45 48 48 54 54 60 72 72"
+===Kernels' specifications===
+====Nokia's kernel====
+ VALUE  VOLTAGE   FREQUENCY     DYNAMIC POWER
+     0.975 V   0 MHz         0.000 V²/us
+     0.975 V   125 MHz       118.828 V²/us
+     1.075 V   250 MHz       288.906 V²/us
+     1.200 V   500 MHz       720.000 V²/us
+     1.275 V   550 MHz       894.094 V²/us
+     1.350 V   600 MHz       1093.500 V²/us
+====titan's LV kernel====
+ VALUE  VOLTAGE   FREQUENCY     DYNAMIC POWER
+     0.975V    0 MHz         0.000 V²/us
+     0.975V    125 MHz       118.828 V²/us
+     1.075V    250 MHz       288.906 V²/us
+     1.200V    500 MHz       720.000 V²/us
+     1.200V    550 MHz       792.000 V²/us
+     1.275V    600 MHz       975.375 V²/us
+     1.275V    700 MHz       1137.938 V²/us
+     1.275V    750 MHz       1219.219 V²/us
+     1.275V    810 MHz       1316.756 V²/us
+     1.275V    850 MHz       1381.781 V²/us
+     1.275V    900 MHz       1463.062 V²/us
+     1.275V    950 MHz       1544.344 V²/us
+     1.350V    1000 MHz      1822.500 V²/us
+     1.500V    1100 MHz      2475.000 V²/us
+     1.500V    1200 MHz      2700.000 V²/us
+====titan's ULV kernel====
+ VALUE  VOLTAGE   FREQUENCY    DYNAMIC POWER
+     0.912V    0 MHz        0.000 V²/us
+     0.912V    125 MHz      103.968 V²/us
+     0.912V    250 MHz      207.936 V²/us
+     1.012V    500 MHz      512.072 V²/us
+     1.075V    550 MHz      635.594 V²/us
+     1.075V    600 MHz      693.375 V²/us
+     1.163V    700 MHz      946.798 V²/us
+     1.163V    750 MHz      1014.427 V²/us
+     1.200V    810 MHz      1166.400 V²/us
+     1.200V    850 MHz      1224.000 V²/us
+     1.275V    900 MHz      1463.062 V²/us
+     1.275V    950 MHz      1544.344 V²/us
+     1.350V    1000 MHz     1822.500 V²/us
+     1.500V    1100 MHz     2475.000 V²/us
+     1.500V    1200 MHz     2700.000 V²/us
+====titan's XLV kernel====
+ VALUE  VOLTAGE   FREQUENCY    DYNAMIC POWER
+     0.975V    0 MHz        0.000 V²/us
+     0.850V    125 MHz      90.312 V²/us
+     0.975V    250 MHz      237.656 V²/us
+     1.012V    500 MHz      512.072 V²/us
+     1.075V    550 MHz      635.594 V²/us
+     1.075V    600 MHz      693.375 V²/us
+     1.163V    700 MHz      946.798 V²/us
+     1.163V    750 MHz      1014.427 V²/us
+     1.200V    810 MHz      1166.400 V²/us
+     1.200V    850 MHz      1224.000 V²/us
+     1.275V    900 MHz      1463.062 V²/us
+     1.275V    950 MHz      1544.344 V²/us
+     1.350V    1000 MHz     1822.500 V²/us
+     1.500V    1100 MHz     2475.000 V²/us
+     1.500V    1150 MHz     2587.500 V²/us
+====titan's ideal kernel====
+ VALUE  VOLTAGE   FREQUENCY    DYNAMIC POWER
+     0.975V    0 MHz        0.000 V²/us
+     0.975V    125 MHz      118.828 V²/us
+     0.975V    250 MHz      237.656 V²/us
+     0.975V    500 MHz      475.312 V²/us
+     1.012V    550 MHz      563.279 V²/us
+     1.075V    600 MHz      693.375 V²/us
+     1.163V    700 MHz      946.798 V²/us
+     1.163V    750 MHz      1014.427 V²/us
+     1.200V    810 MHz      1166.400 V²/us
+     1.200V    850 MHz      1224.000 V²/us
+     1.275V    900 MHz      1463.062 V²/us
+     1.275V    950 MHz      1544.344 V²/us
+     1.350V    1000 MHz     1822.500 V²/us
+     1.500V    1100 MHz     2475.000 V²/us
+     1.500V    1150 MHz     2587.500 V²/us
 [[Category:Power users]]
-[[Category:N900]]