Re: [PATCH 07/15] arm: dts: exynos: Add missing cooling device properties for CPUs

[Krzysztof Kozlowski]

On Wed, May 30, 2018 at 6:38 AM, Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote:
> On 29-05-18, 15:18, Krzysztof Kozlowski wrote:
>> Thanks for the patch.
>>
>> In case of Exynos, the booting CPU always has these information in DT
>> and the booting CPU cannot be changed (chosen by firmware/hardware
>> configuration).
>
> But can the booting CPU be offlined ?
>
> If yes, then this is how things are broken right now.
>
> Build cpufreq driver as module, boot kernel, hotplug out CPU0, insert
> cpufreq driver and that will try to find these properties in CPU1.

OK, I see the possibility although it is still far away from use
cases. You cannot hotplug booting CPU (CPU0) on Exynos kernels. It
never worked. Strictly speaking - offlining will work. But bringing it
online will likely hang the system.

Best regards,
Krzysztof