Re: [PATCH V2] PM / Domains: Return -EPROBE_DEFER if we fail to init or turn-on domain

[Jon Hunter <jonathanh@nvidia.com>]

Hi Geert,

On 06/08/15 12:26, Geert Uytterhoeven wrote:
> Hi Jon,
> 
> On Thu, Aug 6, 2015 at 11:26 AM, Jon Hunter <jonathanh@nvidia.com> wrote:
> 
> [...]
> 
>>>>>>>>> This causes a regression for platforms where:
>>>>>>>>>   1. DT describes the hardware power domains, and
>>>>>>>>>   2. The boot loader or reset state has enabled all power domains, and
>>>>>>>>>   3. Linux doesn't have a driver for the power controller yet.
>>>>>>>>>
>>>>>>>>> Before, devices for which the PM domain couldn't be found just probed and
>>>>>>>>> worked, Now, these devices don't probe anymore, and the kernel fails to boot.
> 
> [...]
> 
>> It still sounds to me that the nodes should be disabled/removed from the
>> dtb. Having a dynamic way to do this would be useful, I can see.
> 
> I had a quick look, and it already seem to exist..
> Hence on platforms not implementing power controllers yet, the early platform
> code could do:
> 
>         struct device_node *np;
>         for_each_node_with_property(dn, "power-domains")
>                 of_remove_property(np, "power-domains");
> 
> Haven't tested that yet, though...

Yes that could be an option, however, it would mean doing this type of
thing for various types of nodes. You mentioned dma was another case.

> Heck, even the core power domain code could do that, if
> CONFIG_PM_GENERIC_DOMAINS=n ;-)

Yes that's true. Hopefully it would WARN too ;-)

Jon

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