Messages in this thread | | | From | Len Brown <> | Subject | [RESEND] [PATCH 0/2] Quiet power limit notification | Date | Thu, 16 May 2013 17:54:04 -0400 |
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[Re-sending for Fenghua, as his e-mail seems to have got lost. In case you receive multiple copies, the patches are unchanged.]
thanks, -Len Brown Intel Open Source Technology Center ---
Power Limit Notification (X86_FEATURE_PLN) was added in Sandy Bridge to give the OS the option of knowing when the package has reached a configured power threshold.
Linux-2.6.36 enabled this feature: 0199114c31798af5b83841b21759b64171060d9b (x86, hwmon: Package Level Thermal/Power: power limit)
It enabld the interrupt, and the interrupt hander added to the MCE log and printed to the console:
printk(KERN_CRIT "CPU%d: %s power limit notification (total events = %lu) printk(KERN_INFO "CPU%d: %s power limit normal\n"
However, these events are quite routine on some systems under some conditions, alarming customers and provoking un-necessary customer support calls.
So the MCE log entry was deleted in Linux-3.3:
29e9bf1841e4f9df13b4992a716fece7087dd237 (x86, mce, therm_throt: Don't report power limit and package level thermal throttle events in mcelog)
Here we delete the corresponding kernel console messages, and then we disable the interrupt by default -- allowing it to be enabled by cmdline for diagnosis purposes.
https://bugzilla.kernel.org/show_bug.cgi?id=36182
This pair of patches applies cleanly back to Linux-3.3.
Documentation/kernel-parameters.txt | 2 ++ arch/x86/kernel/cpu/mcheck/therm_throt.c | 43 ++++++++++++++++++++++++++----------------- 2 files changed, 28 insertions(+), 17 deletions(-)
[1/2] x86 thermal: Disable power limit notification interrupt by default [2/2] x86 thermal: Delete power-limit-notification console messages
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