Re: [PATCH v2 1/2] PM / wakeup: Add callback for wake-up change notification

[Geert Uytterhoeven]

On Wed, Jun 20, 2018 at 3:25 PM Mark Brown <broonie@xxxxxxxxxx> wrote:
> On Wed, Jun 20, 2018 at 02:15:38PM +0200, Rafael J. Wysocki wrote:
> > On Wed, Jun 20, 2018 at 12:35 PM, Mark Brown <broonie@xxxxxxxxxx> wrote:
>
> > > The flip side of that is that either suspend and resume or poweroff are
> > > broken for userspace unless they know about this magic sysfs file which
> > > isn't great either.
>
> > But to me that isn't that much different from an RTC wake alarm, say.
>
> > Enabling it to wake up the system in general isn't sufficient, you
> > also need to actually set the alarm using a different interface.

The RTC wake alarm time is indeed different, as it is not a simple boolean flag.
It is also more natural for the user, who expects to need to find some way to
configure the wake-up time.

> It seems more like hardware breakage we're trying to fix than a feature
> - it's not like it's adding something we didn't have already (like
> setting a time in an alarm where the alarm is an additional thing), more
> just trying to execute on an existing user interface successfully.  I
> can see that there's a case that it doesn't map very well onto the
> standard interfaces so perhaps we have to add something on the side as
> the hardware is just too horrible to fit in with the standard interfaces
> and we have to do that.

My main worry is usability: with a separate sysfs file, we need to document the
file, and the user needs to be aware of it.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

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