I need to disable c-states with p-states enabled on a server. (Xeon E5603). I can find the checkbox in BIOS to disable/enable c-states. However, even if I choose to disable it, the system (CentOS 6.2) still runs under different power stage which means c-states is actually still working.
Another thing I tried is I removed cpuidle driver from kernel and re-built OS. Now c-states is disabled. However, I cannot control p-states anymore (cannot modprobe acpi_cpufreq).
Can anyone help me on this so that I can have both disabled c-states and enabled p-states at the same time? Thanks.