diff options
author | Peter Zijlstra <peterz@infradead.org> | 2014-06-24 14:48:19 +0200 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-07-28 08:06:03 -0700 |
commit | 89d30c2107c85ce3ae1a267f1065aa0fb1e5b310 (patch) | |
tree | b0eb6f8f502331c262fce31d34a3e7af41fada9b /firmware/mts_edge.fw.ihex | |
parent | 025d494281c58dcee04fe3ee2b7fa300e150c95c (diff) |
x86, tsc: Fix cpufreq lockup
commit 3896c329df8092661dac80f55a8c3f60136fd61a upstream.
Mauro reported that his AMD X2 using the powernow-k8 cpufreq driver
locked up when doing cpu hotplug.
Because we called set_cyc2ns_scale() from the time_cpufreq_notifier()
unconditionally, it gets called multiple times for each freq change,
instead of only the once, when the tsc_khz value actually changes.
Because it gets called more than once, we run out of cyc2ns data slots
and stall, waiting for a free one, but because we're half way offline,
there's no consumers to free slots.
By placing the call inside the condition that actually changes tsc_khz
we avoid superfluous calls and avoid the problem.
Reported-by: Mauro <registosites@hotmail.com>
Tested-by: Mauro <registosites@hotmail.com>
Fixes: 20d1c86a5776 ("sched/clock, x86: Rewrite cyc2ns() to avoid the need to disable IRQs")
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Bin Gao <bin.gao@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Stefani Seibold <stefani@seibold.net>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'firmware/mts_edge.fw.ihex')
0 files changed, 0 insertions, 0 deletions