Re: [PATCH] PM / Domains: Correct comment in irq_safe_dev_in_no_sleep_domain()

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Ulf,

On Tue, Jan 31, 2017 at 5:41 PM, Ulf Hansson <ulf.hansson@linaro.org> wrote:
> On 31 January 2017 at 17:17, Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>> On Tue, Jan 31, 2017 at 5:01 PM, Ulf Hansson <ulf.hansson@linaro.org> wrote:
>>> The earlier comment stated that the dev_warn_once() was going to be printed
>>> once per device. Let's fix that, as dev_warn_once() is printed only once,
>>> no matter of the device.
>>
>> While I agree this makes the comment match the code, I think we would serve
>> the users better by printing the warning once per PM domain.
>> Currently the user cannot know if two or more PM domains cannot be powered
>> off due to IRQ safe devices.
>
> Right.
>
>> Perhaps a flag can be added to generic_pm_domain.flags to remember
>> that the warning has been printed before?
>
> That seems like a reasonable adjustment. Allow me to cook a patch on
> top of this one.

Thanks!

> Moreover, I was thinking of considering to check for always on domains
> and perhaps skip printing this message in such cases. Would that make
> sense as well?

That would make sense.

But how would you check that?
By comparing its governor with &pm_domain_always_on_gov?
Note that that is not sufficient, as I think its power_off() callback will still
be called. Only if it fails to power off and returns -EBUSY, it's a real
always-on domain.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds