On 19 August 2013 16:57, Viresh Kumar viresh.kumar@linaro.org wrote:
It wasn't my patch actually.. It only made it visible that's it :) The problem is:
- On suspend all CPUs are removed and so governors are
stopped.
- On resume, handle_update() is called for the boot cpu and
cpu_add_dev for all others.
handle_update() doesn't start governor but only plays with CPUFREQ_GOV_LIMITS.. when we start adding other CPUs and call: cpufreq_add_policy_cpu() which fails in following call:
__cpufreq_governor(policy, CPUFREQ_GOV_STOP);
and so cpufreq_policy_cpu never gets initialized to policy->cpu and stays at -1, and hence the crash.
So, there are few problems with core at this point:
- I don't understand how does the work done in
cpufreq_add_dev() gets done for boot cpu during resume ? And so how does Srivatsa's "frozen" solution really works (I haven't had time to investigate, its not that I couldn't understand it :) )..
- We need to start governor boot cpu in handle_update()
and things would be solved...
Whatever I wrote here was simply _Bullshit_ :(
I am about to send you a fixup patchset that fixes this issue, and yes it was my patch which introduced this problem :(, but because of some mishandling of cpufreq_policy_list :)
-- viresh