[PATCH 2/9] PM / Domains: Remove dev->driver check for runtime PM

[Kevin Hilman]

On Fri, Aug 14, 2015 at 12:24 AM, Geert Uytterhoeven
<geert at linux-m68k.org> wrote:
> Hi Kevin,
>
> On Fri, Aug 14, 2015 at 5:40 AM, Kevin Hilman <khilman at kernel.org> wrote:
>> Geert Uytterhoeven <geert at linux-m68k.org> writes:
>>> On Wed, Aug 12, 2015 at 9:50 PM, Kevin Hilman <khilman at kernel.org> wrote:
>>>> This check might have made sense before PM domains, but with PM domains,
>>>> it's entirely possible to have a simple device without a driver and the
>>>> PM domain handles all the necesary PM, so I think this check
>>>> could/should be removed.
>>>>
>>>> Thoughts?
>>>
>>> Simple devices without a driver aren't handled automatically.
>>> At minimum, the driver should call pm_runtime_enable(), cfr.
>>> drivers/bus/simple-pm-bus.c.
>>
>> That's correct, and in the proof-of-concept stuff I hacked up and in
>> Lina's series, the CPU "devices" do indeed to this.  Without that, they
>> wouldn't end up ever taking this codepath through genpd's
>> runtime_suspend and power_off hooks.
>>
>> Also, I'm not sure if your comment was meant to be an objection to the
>> patch?  or if you're OK with it.
>
> My comment was purely meant as a response to "it's entirely possible to have a
> simple device without a driver and the PM domain handles all the necesary PM".

Right, so if the PM domain does the pm_runtime_enable() for these
"simple" devices without drivers, they can still exist without a
driver, and the PM domain doing all the magic.

> I have no objections to the patch (read: I'm not sufficiently familiar with
> the code to make educated guesses about the side effects of this change ;-).

OK, thanks for clarifiying.

Kevin