tree e8101e5202bfe600f928f3f2400dfd5afa4b54f6
parent 178783622ce0fd629fad21b33b8f8f56b64c5e45
author Will Deacon <will.deacon@arm.com> 1309527492 +0100
committer Russell King <rmk+kernel@arm.linux.org.uk> 1309865843 +0100

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>