[Bug 10062] New: cpufreq scaling for via c3 no longer works

[Bug 10062] New: cpufreq scaling for via c3 no longer works

[bugme-daemon]

http://bugzilla.kernel.org/show_bug.cgi?id=10062

           Summary: cpufreq scaling for via c3 no longer works
           Product: Power Management
           Version: 2.5
     KernelVersion: Linux Rie 2.6.22-14-386 #1 Tue Dec 18 07:34:24 UTC 2007
                    i686 GNU
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: cpufreq
        AssignedTo: cpufreq@www.linux.org.uk
        ReportedBy: bugzilla.kernel.org@rolf.leggewie.biz


It seems the scaling for cpu scaling for VIA C3 CPUs has been missing from the
Kernel for 2.6 kernels.  I am not exactly sure when this stopped working but I
believe it was between the 2.4 and 2.6 switch.  Let me know if there is
anything I can do to provide further information.  I am not always sure where
to look.  I'd be happy to compile new kernels for testing anytime.


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[Bug 10062] cpufreq scaling for via c3 no longer works

[bugme-daemon]

http://bugzilla.kernel.org/show_bug.cgi?id=10062


davej@codemonkey.org.uk changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |REJECTED
         Resolution|                            |INVALID




------- Comment #1 from davej@codemonkey.org.uk  2008-02-25 13:54 -------
It's still there (CONFIG_X86_LONGHAUL).  From the version number it looks like
you're running a vendor kernel ?
Vendor kernels typically disable this module because it isn't very stable on
some systems.  It works fine for some people, but for others they see lockups
after a while.


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[Bug 10062] cpufreq scaling for via c3 no longer works

[bugme-daemon]

http://bugzilla.kernel.org/show_bug.cgi?id=10062


bugzilla.kernel.org@rolf.leggewie.biz changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REJECTED                    |REOPENED
         Resolution|INVALID                     |




------- Comment #2 from bugzilla.kernel.org@rolf.leggewie.biz  2008-03-07 03:34 -------
Dave, thank you for your comment.  I have been enduring this problem for quite
some time, trying out all kinds of different things in the process.  While you
are right that normally I run a vendor-supplied kernel, I did test this with a
couple of self-compiled kernels, too.  I'll try to do this again as soon as
possible, but I don't expect any changes.

# grep -i longhaul /boot/config-2.6.22-14-386 
CONFIG_X86_LONGHAUL=m
# modprobe longhaul
FATAL: Error inserting longhaul
(/lib/modules/2.6.22-14-386/kernel/arch/i386/kernel/cpu/cpufreq/longhaul.ko):
No such device
# grep -i longhaul /var/log/syslog
Mar  7 12:30:51 Rie kernel: [3705563.931789] longhaul: VIA C3 'Samuel' [C5A]
CPU detected.  Longhaul v1 supported.
Mar  7 12:30:51 Rie kernel: [3705563.931925] longhaul: No ACPI support.
Unsupported northbridge.

So, it looks like the module is there, but it does not work as expected.

https://bugs.launchpad.net/bugs/50431 has some more information.


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[Bug 10062] cpufreq scaling for via c3 no longer works

[bugme-daemon]

http://bugzilla.kernel.org/show_bug.cgi?id=10062


protasnb@gmail.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |protasnb@gmail.com,
                   |                            |rafalbilski@interia.pl




------- Comment #3 from protasnb@gmail.com  2008-06-01 18:53 -------
There was a commit that tried to deal with longhaul erratas:
commit 52a2638bff063acb28ba3355891c49cc240cc98b
Author: Rafal Bilski <rafalbilski@interia.pl>
Date:   Sun Oct 7 00:24:32 2007 -0700

    Longhaul: add auto enabled "revid_errata" option

    VIA C3 Ezra-T has RevisionID equal to 1, but it needs RevisionKey to be 0
    or CPU will ignore new frequency and will continue to work at old
    frequency.  New "revid_errata" option will force RevisionKey to be set to
    0, whatever RevisionID is.

    Additionaly "Longhaul" will not silently ignore unsuccessful transition.
    It will try to check if "revid_errata" or "disable_acpi_c3" options need to
    be enabled for this processor/system.

    Same for Longhaul ver.  2 support.  It will be disabled if none of above
    options will work.

     Best case scenario (with patch apllied and v2 enabled):
     longhaul: VIA C3 'Ezra' [C5C] CPU detected.  Longhaul v2 supported.
     longhaul: Using northbridge support.
     longhaul: VRM 8.5
     longhaul: Max VID=1.350  Min VID=1.050, 13 possible voltage scales
     longhaul: f: 300000 kHz, index: 0, vid: 1050 mV
     [...]
     longhaul: Voltage scaling enabled.
     Worst case scenario:
     longhaul: VIA C3 'Ezra-T' [C5M] CPU detected.  Powersaver supported.
     longhaul: Using northbridge support.
     longhaul: Using ACPI support.
     longhaul: VRM 8.5
     longhaul: Claims to support voltage scaling but min & max are both 1.250.
Voltage scaling disabled
     longhaul: Failed to set requested frequency!
     longhaul: Enabling "Ignore Revision ID" option.
     longhaul: Failed to set requested frequency!
     longhaul: Disabling ACPI C3 support.
     longhaul: Disabling "Ignore Revision ID" option.
     longhaul: Failed to set requested frequency!
     longhaul: Enabling "Ignore Revision ID" option.

You can enable CPU_FREQ_DEBUG and place cpufreq.debug=2 for driver debug on the
boot command line.


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