Comment 0 for bug 1390902

On Ubuntu:
> lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 14.04.1 LTS
Release: 14.04
Codename: trusty

> uname -a
Linux desk 3.13.0-39-generic #66-Ubuntu SMP Tue Oct 28 13:30:27 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

on all my Intel Core i5 or i7 systems (desktop and laptop) CPU scaling does not work out of the box:
> cpufreq-info
cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to <email address hidden>, please.
analyzing CPU 0:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 10.0 us.
  hardware limits: 1.60 GHz - 3.50 GHz
  available frequency steps: 3.50 GHz, 3.50 GHz, 3.40 GHz, 3.20 GHz, 3.10 GHz, 3.00 GHz, 2.80 GHz, 2.70 GHz, 2.50 GHz, 2.40 GHz, 2.30 GHz, 2.10 GHz, 2.00 GHz, 1.90 GHz, 1.70 GHz, 1.60 GHz
  available cpufreq governors: conservative, ondemand, userspace, powersave, performance
  current policy: frequency should be within 3.50 GHz and 3.50 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 3.50 GHz.
  cpufreq stats: ...

The problem is that although the hardware limits are correctly detected only the "range" between 3.50 and 3.50 GHz is used.

A workaround that works on all of my systems is:
> cat cpufreq_workaround.sh
#!/bin/sh
min_freq=$(cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies | awk "{ print \$NF }")
echo "Setting scaling_min_freq to $min_freq"
for i in `seq 0 7`; do echo $min_freq > /sys/devices/system/cpu/cpu$i/cpufreq/scaling_min_freq; done

afterwards:
> cpufreq-info
cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to <email address hidden>, please.
analyzing CPU 0:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 10.0 us.
  hardware limits: 1.60 GHz - 3.50 GHz
  available frequency steps: 3.50 GHz, 3.50 GHz, 3.40 GHz, 3.20 GHz, 3.10 GHz, 3.00 GHz, 2.80 GHz, 2.70 GHz, 2.50 GHz, 2.40 GHz, 2.30 GHz, 2.10 GHz, 2.00 GHz, 1.90 GHz, 1.70 GHz, 1.60 GHz
  available cpufreq governors: conservative, ondemand, userspace, powersave, performance
  current policy: frequency should be within 1.60 GHz and 3.50 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 1.60 GHz.
...

This issue persisted over all dist-upgrades since installing Ubuntu 14.04.1.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-39-generic 3.13.0-39.66
ProcVersionSignature: Ubuntu 3.13.0-39.66-generic 3.13.11.8
Uname: Linux 3.13.0-39-generic x86_64
NonfreeKernelModules: fglrx
ApportVersion: 2.14.1-0ubuntu3.5
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: ahb 3853 F.... pulseaudio
 /dev/snd/controlC0: ahb 3853 F.... pulseaudio
Date: Sun Nov 9 13:54:23 2014
HibernationDevice: RESUME=UUID=1968620e-56f2-4ec6-b4ae-d2c601e8caa5
InstallationDate: Installed on 2014-08-28 (72 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
IwConfig:
 eth0 no wireless extensions.

 eth1 no wireless extensions.

 lo no wireless extensions.
MachineType: To Be Filled By O.E.M. To Be Filled By O.E.M.
ProcFB:
 0 VESA VGA
 1 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-39-generic root=UUID=98ea3432-7344-4034-8652-46e5edf53f5b ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-39-generic N/A
 linux-backports-modules-3.13.0-39-generic N/A
 linux-firmware 1.127.8
RfKill:

SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/14/2012
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: P1.40
dmi.board.name: Z77 Extreme4
dmi.board.vendor: ASRock
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrP1.40:bd05/14/2012:svnToBeFilledByO.E.M.:pnToBeFilledByO.E.M.:pvrToBeFilledByO.E.M.:rvnASRock:rnZ77Extreme4:rvr:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.name: To Be Filled By O.E.M.
dmi.product.version: To Be Filled By O.E.M.
dmi.sys.vendor: To Be Filled By O.E.M.