「ユーザースペース」cpufreqガバナーは使用できず、CPU周波数を設定できません。

私のラップトップ（Linuxを実行）でCPU周波数を変更しようとしましたが、成功しませんでした。
以下はいくつかの詳細です。

# uname -a
Linux yoga 3.12.21-gentoo-r1 #4 SMP Thu Jul 10 17:32:31 HKT 2014 x86_64 Intel(R) Core(TM) i5-3317U CPU @ 1.70GHz GenuineIntel GNU/Linux

# cpufreq-info
cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to [email protected], please.
analyzing CPU 0:
  driver: intel_pstate
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 0.97 ms.
  hardware limits: 800 MHz - 2.60 GHz
  available cpufreq governors: performance, powersave
  current policy: frequency should be within 800 MHz and 2.60 GHz.
                  The governor "powersave" may decide which speed to use
                  within this range.
  current CPU frequency is 2.42 GHz (asserted by call to hardware).
(similar information for cpus 1, 2 and 3)

# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors
performance powersave

もともとユーザースペースレギュレータをカーネルに構築しましたが、それをモジュールとして構築しようとしました（同じ結果）。上記のコマンドを実行したときにロードされました（ロード中にシステムメッセージが見つかりませんでした）。

# lsmod
Module                  Size  Used by
cpufreq_userspace       1525  0
(some other modules)

周波数を変更するコマンドは次のとおりです。

# cpufreq-set -f 800MHz
Error setting new values. Common errors:
- Do you have proper administration rights? (super-user?)
- Is the governor you requested available and modprobed?
- Trying to set an invalid policy?
- Trying to set a specific frequency, but userspace governor is not available,
   for example because of hardware which cannot be set to a specific frequency
   or because the userspace governor isn't loaded?

# cpufreq-set -g userspace  
Error setting new values. Common errors:
- Do you have proper administration rights? (super-user?)
- Is the governor you requested available and modprobed?
- Trying to set an invalid policy?
- Trying to set a specific frequency, but userspace governor is not available,
   for example because of hardware which cannot be set to a specific frequency
   or because the userspace governor isn't loaded?

どんなアイデアがありますか？