cpufreq: Fixes for 3.12

Hi Rafael,

You recently did this:

commit 878f6e074e9a7784a6e351512eace4ccb3542eef

Author: Rafael J. Wysocki <[email protected]>
Date:   Sun Aug 18 15:35:59 2013 +0200

Revert "cpufreq: Use cpufreq_policy_list for iterating over policies"

Revert commit eb60852 (cpufreq: Use cpufreq_policy_list for iterating over policies), because it breaks system suspend/resume on multiple machines.

It either causes resume to block indefinitely or causes the BUG_ON() in lock_policy_rwsem_##mode() to trigger on sysfs accesses to cpufreq attributes.

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This patchset gets the reverted patch back along with few supporting patches. Cause of the initial problem you observed was this:

- At suspend all CPUs are removed leaving boot cpu. At this time policies aren't freed and also aren't removed from cpufreq_policy_list. And per-cpu variable cpufreq_cpu_data is marked as NULL.
- At resume CPUs other than boot cpu called __cpufreq_add_dev(). The tricky change that was introduced by my patch was: We iterate over list of policies instead of CPUs, where we used to get policy structure associated with CPUs using per-cpu variable. Which used to be NULL for first CPU of a policy that turned up. For the first cpu we don't want to call cpufreq_add_policy_cpu() but want __cpufreq_add_add() to continue.

When we called cpufreq_add_policy_cpu() it tried to stop the governor (which was already stopped) and hence errors leading into unstable state.

This patchset fixes these issues and is tested with suspend-resume over my thinkpad with ubuntu. Apart from minor cleanups it removes policy from cpufreq_policy_list in case of suspend/resume as well and hence we will never call cpufreq_add_policy_cpu() for first cpu of a policy.

--
viresh

Viresh Kumar (5):
cpufreq: align closing brace '}' of an if block
cpufreq: remove policy from cpufreq_policy_list in system suspend
cpufreq: remove unnecessary check in __cpufreq_governor()
cpufreq: remove cpufreq_policy_cpu per-cpu variable
cpufreq: Use cpufreq_policy_list for iterating over policies

 drivers/cpufreq/cpufreq.c | 77 +++++++++++++++--------------------------------
 1 file changed, 24 insertions(+), 53 deletions(-)

1.7.12.rc2.18.g61b472e