From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dirk Brandewie <dirk.brandewie@gmail.com>
Subject: [REGRESSION] Commit a66b2e50 "Preserve sysfs files across suspend/resume"
 causes a regression in intel_pstate
Date: Wed, 10 Jul 2013 09:15:12 -0700
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To: cpufreq <cpufreq@vger.kernel.org>
Cc: dirk.brandewie@gmail.com, "Rafael J. Wysocki" <rjw@sisk.pl>, srivatsa.bhat@linux.vnet.ibm.com, durgadoss.r@intel.com, "Jarzmik, Robert" <robert.jarzmik@intel.com>, tianyu.lan@intel.com

Hi All,

Tianyu debugged into https://bugzilla.kernel.org/show_bug.cgi?id=59781 and found
that commit a66b2e50 is causing the regression.

Tianyu has proposed a fix (patch attached to bugzilla) but having scaling
drivers receive hotplug notifications through two paths seems weird.

Looking at the core code and some of the other scaling drivers
I don't see an obvious fix.  Maybe adding optional suspend/resume callbacks
to the scaling driver interface?

All the scaling drivers that need to do stateful  work in the init/exit
callbacks are being affected by this change so I think there are other
subtle side-effects out there that haven't been noticed yet.

I am not sure how we should proceed here?

Thoughts?
--Dirk