Re: [PATCH v3 5/5] thermal: cpu_cooling: update the cpu device when cpufreq updates the policy cpu

[Viresh Kumar]

On 3 March 2015 at 17:11, Kapileshwar Singh <kapileshwar.singh@xxxxxxx> wrote:
> Yes I indeed tested the case where we cache the device pointer of the CPU for which the OPP's are populated.
> When this CPU is hotplugged out, it invalidates the device pointer itself. Here are the error we get in dmesg:

What do you mean by 'invalidates the device pointer' ? that cpu_dev is NULL ?

> <3>[67203.216774] opp_get_voltage: Invalid parameters
> <3>[67203.326774] opp_get_voltage: Invalid parameters
> <3>[67203.326774] opp_get_voltage: Invalid parameters

Have you handwritten them ? Why don't they precede with dev_pm_* ??

>
> Which happens because:
>
> unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
> {
> ..
>         tmp_opp = rcu_dereference(opp);
>         if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available)
>                 pr_err("%s: Invalid parameters\n", __func__);

This %s should print routine name ..

>         else
> ..
>
> Which happens when
>
>         opp = dev_pm_opp_find_freq_exact(cpufreq_device->cpu_dev, freq_hz,
>                                          true);
>
> returns a an erroneous or NULL OPP or the opp is unavailable (in the above condition)

Please goto the depth of this thing, as I don't think it should happen.

Over that I was asking you if you have tested the solution Javi gave,
because OPPs
wouldn't have been initialized for other CPUs once policy->cpu goes down.
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