* Temporarily disabling SNB package C-states?
@ 2013-07-10 21:03 Andy Lutomirski
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From: Andy Lutomirski @ 2013-07-10 21:03 UTC (permalink / raw)
To: x86, linux-pm, Len Brown, linux-i2c
I wrote a driver for the SNB Xeon iMC SMBUS adapter, but it doesn't
work right due to erratum BT109 (I think). To work around it, I need
to keep a particular cpu package awake for a few ms when my driver is
in use. Is there a good way to do this? So far I've thought of:
- pm_qos. This seems hacky and it will keep a lot more of the system
awake than I need.
- Hook into cpuidle to keep a single core awake.
- Actually run on the target package, possibly in a kthread or
workqueue, and stay busy. Ugh.
- Fiddle with the package c-state limit (in
MSR_PKG_CST_CONFIG_CONTROL) directly. This seems like it's asking for
trouble. I'd have to coordinate with intel_idle, presumably.
Any ideas/suggestions?
--Andy
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2013-07-10 21:03 Temporarily disabling SNB package C-states? Andy Lutomirski
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