[Bug 286133] [NEW] acpi-cpufreq does not recognize all frequencies for E8500 CPU

[Dinko Korunic]

Public bug reported:

Binary package hint: linux-image-generic

I have E8500 Intel Core2Duo CPU:

vampirella:~ $ grep model /proc/cpuinfo
model		: 23
model name	: Intel(R) Core(TM)2 Duo CPU     E8500  @ 3.16GHz
...

It seems that kernel acpi cpufreq module detects and uses only lowest
and highest frequency, instead one for each frequency multiplier -- CPU
stepping supports following: 6x333, 7x333, 8x333, 9x333 and 9.5x333.

The relevant output follows:

vampirella:~ $ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
3166000 2000000 

vampirella:~ $ cat /sys/devices/system/cpu/cpu0/cpufreq/stats/trans_table
   From  :    To
         :   3166000   2000000 
  3166000:         0        62 
  2000000:        61         0 

vampirella:~ $ cpufreq-info
cpufrequtils 002: cpufreq-info (C) Dominik Brodowski 2004-2006
Report errors and bugs to linux at brodo.de, please.
analyzing CPU 0:
  driver: acpi-cpufreq
  CPUs which need to switch frequency at the same time: 0
  hardware limits: 2.00 GHz - 3.17 GHz
  available frequency steps: 3.17 GHz, 2.00 GHz
  available cpufreq governors: userspace, powersave, ondemand, conservative, performance
  current policy: frequency should be within 2.00 GHz and 3.17 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 2.00 GHz.
...

CPU is not overclocked and frequency scaling works fine in Windows
XP/Vista. MBO is Gigabyte GA-P35-DS3 with latest F14a BIOS and CPU is
recognized correctly. Gigabyte's MIT (auto-overclocking) is not enabled.

Ondemand stepping works generally OK, but as I said -- frequency jumps
from lowest to highest speed.

** Affects: linux-meta (Ubuntu)
     Importance: Undecided
         Status: New

-- 
acpi-cpufreq does not recognize all frequencies for E8500 CPU
https://bugs.launchpad.net/bugs/286133
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