Hi Thomas, Thanks for your suggestions. I quickly tested the following grep -r cpufreq_register_driver arch/.../ It did not find the driver in the architecture I am targeting ( ppc ). However drivers were found for other architectures. Am I missing soomething ? Regards Rup On Wed, Jul 22, 2009 at 4:25 PM, Thomas Renninger<trenn@xxxxxxx> wrote: > On Wednesday 22 July 2009 12:17:59 Rupjyoti Sarmah wrote: >> Hi All, >> >> I am working on a PowerPC target. I want to change the CPU clock rate >> dynamically. Could you please suggest/point me to >> >> 1) the steps to do so ( I intend to execute a command from command >> line ) >> 2) Necessary files/libraries that might be needed >> >> I would appreceiate your suggestions, I am using linux 2.6.30 kernel. > Find the corresponding PowerPC low-level cpufreq driver for your HW. > I am not familiar with PowerPC cpufreq drivers you should find them by > doing: > grep -r cpufreq_register_driver arch/.../ > Make sure it loads successfully. > You then probably want to use the userspace governor: > modprobe cpufreq_userspace, or better compile it into the kernel > and additionally set: > CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE=y > then you do not need to do: > echo userspace >/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor > Now you can use: > cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies > and > echo xy >/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed > > Instead of accessing /sys/devices/system/cpu/cpu*/cpufreq > directly you should better use the cpufrequtils project/package > which already provides you most of above and more with simple command(s) > and param(s) (once you find a low-level driver serving your HW). > > Thomas > -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
