[PATCH V5 16/20] ARM: exynos: cpuidle: Move the power sequence call in the cpu_pm notifier

[Chander Kashyap]

On Thu, Jun 26, 2014 at 3:18 PM, Tomasz Figa <t.figa at samsung.com> wrote:
> Hi Chander,
>
> On 26.06.2014 11:07, Chander Kashyap wrote:
>> On Fri, Apr 11, 2014 at 4:10 PM, Daniel Lezcano
>> <daniel.lezcano at linaro.org> wrote:
>
> [snip]
>
>>> @@ -359,6 +373,7 @@ static int exynos_cpu_pm_notifier(struct notifier_block *self,
>>>         switch (cmd) {
>>>         case CPU_PM_ENTER:
>>>                 if (cpu == 0) {
>>> +                       exynos_pm_central_suspend();
>>>                         exynos_cpu_save_register();
>>>                 }
>>>                 break;
>>> @@ -368,6 +383,7 @@ static int exynos_cpu_pm_notifier(struct notifier_block *self,
>>>                         if (!soc_is_exynos5250())
>>>                                 scu_enable(S5P_VA_SCU);
>>>                         exynos_cpu_restore_register();
>>> +                       exynos_pm_central_resume();
>>
>> This notifier is called for system wide suspend and cpuidle.
>>
>> In case of Exynos cpuidle only AFTR and LPA state need to program
>> central_sequencer and store/restore the registers.
>>
>> But in 5420 (core-power-down), this is not required, and causing the regression.
>>
>> Hence need to remove this notifier, or need to find a way to
>> differentiate the cpuidle state.
>
> This patch is already present in v3.16. Moreover, Exynos5420 cpuidle has
> not been merged yet. This means that this issue is not a regression and
> I believe any further work on this should be carried out as further
> patches on top of this change.
>
> Anyway, this change has introduced a regression, though, but in another
> area - it broke suspend, at least on Exynos4-based devices, because now
> certain steps are performed twice. I've sent a patch for 3.16-rc3 to fix
> this by dropping custom suspend-specific syscore ops, effectively moving
> most of the handling to CPU PM notifier, which also matches requirements
> of AFTR and lower power states. See [1].
>
> [1]
> http://www.mail-archive.com/linux-samsung-soc@vger.kernel.org/msg32935.html
>
> However, in this case, moving back to suspend-specific syscore_ops and
> simply duplicating some code for lower cpuidle states might be a better
> option. Care to send a patch (fix for 3.16, replacing mine) or I should
> do it?

Yes need to move the common code to lower cpuildle implementation and
removing the notifier all together.
I will do it and send the patch.


>
> Best regards,
> Tomasz
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