New: cpufreq scaling for via c3 no longer works
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: [email protected]
ReportedBy: [email protected]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
http://bugzilla.kernel.org/show_bug.cgi?id=10062
[email protected] changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |REJECTED
Resolution| |INVALID------- Comment #1 from [email protected] 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
In reply to [email protected]http://bugzilla.kernel.org/show_bug.cgi?id=10062
[email protected] changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|REJECTED |REOPENED
Resolution|INVALID |------- Comment #2 from [email protected] 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
In reply to [email protected]http://bugzilla.kernel.org/show_bug.cgi?id=10062
[email protected] changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |[email protected], | |[email protected]
------- Comment #3 from [email protected] 2008-06-01 18:53 ------- There was a commit that tried to deal with longhaul erratas:
commit 52a2638bff063acb28ba3355891c49cc240cc98b
Author: Rafal Bilski <[email protected]> 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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