From: Will Deacon <will.deacon@arm.com>
Date: Fri, 1 Jul 2011 13:38:12 +0000 (+0100)
Subject: ARM: 6989/1: perf: do not start the PMU when no events are present
X-Git-Tag: v3.0-rc7~13^2~7
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f4f38430c94c38187db73a2cf3892cc8b12a2713;p=pandora-kernel.git

ARM: 6989/1: perf: do not start the PMU when no events are present

armpmu_enable can be called in situations where no events are present
(for example, from the event rotation tick after a profiled task has
exited). In this case, we currently start the PMU anyway which may
leave it active inevitably without any events being monitored.

This patch adds a simple check to the enabling code so that we avoid
starting the PMU when no events are present.

Cc: <stable@kernel.org>
Reported-by: Ashwin Chaugle <ashwinc@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---

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