[Bugme-new] [Bug 8950] New: Incorrect hardware limits reported by acpi-cpufreq on Intel Q6600

[bugme-daemon at bugzilla.kernel.org]

http://bugzilla.kernel.org/show_bug.cgi?id=8950

           Summary: Incorrect hardware limits reported by acpi-cpufreq on
                    Intel Q6600
           Product: ACPI
           Version: 2.5
     KernelVersion: 2.6.23-rc3
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: Power-Processor
        AssignedTo: acpi_power-processor at kernel-bugs.osdl.org
        ReportedBy: mbrooker at rrsg.ee.uct.ac.za


Most recent kernel where this bug did not occur: N/A (acpi-cpufreq would not
load on previous versions)
Distribution: Kubuntu 7.04 x86-64
Hardware Environment: Intel Core 2 Quad Q6600, XFX NForce 650i Ultra mainboard
(with latest BIOS)
Software Environment: Stock Kubuntu 7.04 with security updates
Problem Description: Cpufreq did not work at all on this setup on the Kubuntu
stock kernel (2.6.20), so I built 2.6.22-rc3, with Ubuntu config (updated with
make oldconfig). Now acpi-cpufreq loads, but cpufreq-info reports:

""""
available frequency steps: 44.61 GHz, 29.74 GHz
  available cpufreq governors: conservative, ondemand, userspace, powersave,
performance
  current policy: frequency should be within 29.74 GHz and 29.74 GHz.
"""

/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies lists:

"""
44613000 29742000
"""

Manually changing the governor to "userspace" and changing the frequency with 

echo 44613000 > scaling_cur_freq

changes the reported current frequency, but has no effect on system performance
(verified with simple benchmarks).

Cpu frequency management is enabled in the BIOS. Scaling works fine on Windows
XP Pro.

Steps to reproduce:


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