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wiki:cpu_frequency_scaling_basics [2011/11/20 15:18] – [#INTRODUCTION] bmarkuswiki:cpu_frequency_scaling_basics [2014/12/26 06:43] (current) – bmarkus
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 In most cases it works fine and you do not need any additional action. In most cases it works fine and you do not need any additional action.
 +
 +However, as there are certain setups where either not all required drivers are automatically loaded and/or where the 'ondemand' governor gets prevented from being enabled (due to latency being too high), it is a good idea to do a check - based on info which follows - whenever running TC4 for the first time with a specific processor or chipset.
  
  
 ===== #VIEW CPU FREQUENCY INFORMATION ===== ===== #VIEW CPU FREQUENCY INFORMATION =====
  
-If you want to view actual CPU frequency settings, install cpufreq-utils.tcz extension and use command:+If you want to view actual CPU frequency settings, install cpufrequtils.tcz extension and use command:
  
 cpufreq-info cpufreq-info
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 userspace - allows userspace programs (or any process running as root) to set the frequency userspace - allows userspace programs (or any process running as root) to set the frequency
  
-Above governors are modules, loaded automatically when needed, but you can modprobe them before using. TC default is ondemand.+Above governors are modules, loaded automatically when needed, but you can modprobe them before using. TC default is 'ondemand'.
  
-For most systems, the Ondemand governor can provide the best compromise between heat emission, power consumption, performance, and manageability. When the system is only busy at specific times of the day, the Ondemand governor will automatically switch between maximum and minimum frequency depending on the load without any further intervention.+For most systems, the 'ondemand' governor can provide the best compromise between heat emission, power consumption, performance, and manageability. When the system is only busy at specific times of the day, the 'ondemand' governor will automatically switch between maximum and minimum frequency depending on the load without any further intervention.
  
  
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 +===== #TROUBLESHOOTING =====
 +
 +The following relates to a Pentium M under TC3.8.4 (2.6.33.3 kernel) running on a Dell Precision M70\\
 +laptop, but may still be applicable if you run into a similiar problem.\\
 +Installed cpufrequtils and selected ondemand govenor. The policy line from the cpufreq-info command read:\\
 +<code>current policy: frequency should be within 800 MHz and 800 MHz.</code>
 +indicated that CPU was locked at 800Mhz. Executing the command:
 +<code>cat /sys/devices/system/cpu/cpu0/cpufreq/bios_limit</code>
 +returned the value 800000 (frequency in Khz). Using the boot code:
 +<code>processor.ignore_ppc=1</code>
 +fixed that. Now bios_limit contains 2267000 (2.267Ghz), the maximum speed for this CPU. Checking\\
 +\proc\cpuinfo several times showed that the frequency was bouncing between 800Mhz and 2.27Ghz\\
 +even though the machine was not doing anything. Changing the governor to conservative fixed that.\\
 +For links to bug reports that helped solve this problem, see:\\
 +http://forum.tinycorelinux.net/index.php/topic,14917.msg85013.html#msg85013
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