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From: Stewart Smith <stewart@linux.vnet.ibm.com>
To: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>, rjw@rjwysocki.net
Cc: joel@jms.id.au, viresh.kumar@linaro.org, linuxppc-dev@ozlabs.org,
 linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
 Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Subject: Re: [PATCH v5 2/6] powerpc/powernv: Add definition of OPAL_MSG_OCC
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References: <1437033863-15864-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com>
 <1437033863-15864-3-git-send-email-shilpa.bhat@linux.vnet.ibm.com>
Date: Mon, 10 Aug 2015 10:23:58 +1000
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Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com> writes:
> Add OPAL_MSG_OCC message definition to opal_message_type to receive
> OCC events like reset, load and throttled. Host performance can be
> affected when OCC is reset or OCC throttles the max Pstate.
> We can register to opal_message_notifier to receive OPAL_MSG_OCC type
> of message and report it to the userspace so as to keep the user
> informed about the reason for a performance drop in workloads.
>
> The reset and load OCC events are notified to kernel when FSP sends
> OCC_RESET and OCC_LOAD commands.  Both reset and load messages are
> sent to kernel on successful completion of reset and load operation
> respectively.

How is this done on OpenPower systems? Explanation involving just what
OPAL does is likely better, rather than explaining in context of FSP,
which Linux has no real knowledge of (OPAL provides all abstraction of
it).