[root@localhost cpufreq]# modprobe acpi-cpufreq FATAL: Error inserting acpi_cpufreq (/lib/modules/2.6.32-131.17.1.el6-0.11.smp.gcc4.4.x86_64/kernel/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.ko): No such device
Go to your Dell BIOS setting and look for Power Management. Once you inside the Power Management window, look for the Power Management setting. Change the setting to OS Control if is different setting. Reboot and you should be able to load the acpi-cpufreq driver successfully.For more information on Dell Power Management, please go to this link and look for BIOS based P-state management.