From: Andy Lutomirski <luto@amacapital.net>
To: x86@kernel.org, linux-pm@vger.kernel.org,
Len Brown <lenb@kernel.org>,
linux-i2c@vger.kernel.org
Subject: Temporarily disabling SNB package C-states?
Date: Wed, 10 Jul 2013 14:03:20 -0700 [thread overview]
Message-ID: <CALCETrWFVbTDy1u6bpe6h6fGMZHpOvKa3VmzmJ7cej9WOqFiWg@mail.gmail.com> (raw)
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
reply other threads:[~2013-07-10 21:03 UTC|newest]
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