PRECHANGE and POSTCHANGE notifiers must be called in groups, i.e either both should be called or both shouldn't be.
In case we have started PRECHANGE notifier and found an error, we must call POSTCHANGE notifier with freqs.new = freqs.old to guarantee that sequence of calling notifiers is complete.
This isn't obeyed by many of the drivers and core wasn't forcing it.
This patchset first fixes all the driver to follow it strictly and then adds some protection against this. Now, we keep track of the last transaction and see if something went wrong.
Last patch is intentionally kept towards the end, so that git bisect still works well for all the faulty drivers.
This is pushed here and a pull request for 3.11 would be sent after few days.
git://git.linaro.org/people/vireshk/linux.git cpufreq-fix-notification
Viresh Kumar (13): cpufreq: acpi: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: arm-big-little: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: davinci: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: dbx500: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: e_powersave: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: exynos: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: imx6q: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: omap: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: pcc: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: powernow-k8: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: s3c64xx: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: tegra: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: make sure frequency transitions are serialized
drivers/cpufreq/acpi-cpufreq.c | 6 ++++-- drivers/cpufreq/arm_big_little.c | 4 +--- drivers/cpufreq/cpufreq.c | 9 +++++++++ drivers/cpufreq/davinci-cpufreq.c | 3 +++ drivers/cpufreq/dbx500-cpufreq.c | 4 ++-- drivers/cpufreq/e_powersaver.c | 3 +++ drivers/cpufreq/exynos-cpufreq.c | 10 ++++++++-- drivers/cpufreq/imx6q-cpufreq.c | 17 +++++++++++------ drivers/cpufreq/omap-cpufreq.c | 6 +++--- drivers/cpufreq/pcc-cpufreq.c | 2 ++ drivers/cpufreq/powernow-k8.c | 6 +++--- drivers/cpufreq/s3c64xx-cpufreq.c | 8 ++++++-- drivers/cpufreq/tegra-cpufreq.c | 4 ++-- 13 files changed, 57 insertions(+), 25 deletions(-)