olliv / eeefsb Goto Github PK

This kernel module is intended mainly for eee PC 901 over/underclocking. In the
future it will hopefuly support cpufreqd and could be used for CPU speed
stepping and smart power control etc.

Maximum allowed CPU speed is now set to (around) 1806 MHz (actual could be
little lower). Little bit smarter fan control for higher frequencies is now
available but it could be still smarter.
I have heard that 2 GHz is achievable with some tuning and manual fan
control so I keep hacking whenever I have sufficient time slots
available.

Other things I have plans for is improving battery performance while on sleep
mode. Motivation for this comes from the fact that eee PC's EC doesn't really
seem to do much to save energy while the laptop is in sleep mode and I think
there is still some unused tricks to get this better.

The module itself is in the module/ directory.  To build and insert the
module into your kernel:
    cd module
    make
    insmod eeefsb.ko

Note: Kernel has to be loaded with acpi_enforce_resources=lax option and
      it could be necessary to add i2c-i801 into /etc/modules.

Usage:  once the module has been inserted, several files will appear in the
/proc/eeefsb directory:

    cpu_freq    - Set/Read current cpu clock speed (safety limits are set from options.h)
    bus_control - Reading this file will return the current FSB and voltage settings,
                  while writing to this file will change the FSB and voltage.  The
                  format of this file is three integers:
                  <CPU PLL N multiplier>  <CPU PLL M divisor> <PCI PLL M divider>  <CPU voltage>
                  CPU voltage is 0 for "low" and 1 for "high".
    fan_rpm     - The current speed of the fan in revolutions per minute.
    fan_speed   - The current speed (0-100%) the fan is set to.
    fan_manual  - When 0, the embedded controller turns the fan on and off
                  according to the CPU temperature.  When 1, writing to
                  fan_speed will change the speed of the fan;  the embedded
                  controller makes no changes on its own.
    temperature - The temperature of the CPU (in degrees C).

Note that when the fan is in manual mode, IT IS POSSIBLE TO DESTROY YOUR CPU!
It appears that the embedded controller will happily allow the temperature to
reach 90C (the CRITICAL temperature of the CPU), at which point a thermal
shutdown will be initiated.  This will turn the fan to 100%, throttle the CPU,
and probably even shutdown the machine.  Your CPU may or may not survive this
treatment...