Hi!
> > > I had an idea of using an enum type encompassing all of the power states
> > > defined for various platforms and serving both as a registry (to ensure
> > > the
> > > uniqueness of the values assigned to the states) and a common ground
> > > between platforms and drivers.
> > >
> > > Something like:
> > >
> > > enum platform_target_state {
> > > PLATFORM_STATE_UNKNOWN = -1,
> > > PLATFORM_STATE_WORKING = 0,
> > > PLATFORM_STATE_ACPI_S1,
> > > PLATFORM_STATE_ACPI_S2,
> > > PLATFORM_STATE_ACPI_S3,
> > > PLATFORM_STATE_MY_BOARD_1_GATE_CLOCKS,
> > > PLATFORM_STATE_MY_BOARD_1_GATE_POWER,
> > > PLATFORM_STATE_ANOTHER_BOARD_DO_CRAZY_STUFF,
> > > ...
> > > };
> > >
> > > and define ->target_state to return a value of this type.
> > >
> > > Then, if a driver sees one of these and recognizes that value, it should
> > > know exactly what to do.
> >
> > Remind me why this is good idea?
>
> Because there are drivers that need to do specific things during
> suspend on a specific board when it goes into a specific state as a
> whole.
We have seen driver that cares about voltage to his device being
lost. That's reasonable.
Inquiring what the platform target state is... is not.
> > If board wants to know if certain regulator stays online during
> > suspend, it should invent an API for _that_.
>
> Ideally, yes. However, that may be problematic for multiplatform kernels,
> because they would need to have all of those APIs built in and the driver
> code to figure out which API to use would be rather nasty.
Lets do it the right way. Big enum is wrong.
We already have
struct regulator_state {
int uV; /* suspend voltage */
unsigned int mode; /* suspend regulator operating mode */
int enabled; /* is regulator enabled in this suspend state */
int disabled; /* is the regulator disabled in this suspend state */
};
* struct regulation_constraints - regulator operating constraints.
* @state_disk: State for regulator when system is suspended in disk
* mode.
* @state_mem: State for regulator when system is suspended in mem
* mode.
* @state_standby: State for regulator when system is suspended in
* standby
* mode.
. So it seems that maybe we should tell the drivers if we are entering
"state_mem" or "state_standby" (something I may have opposed, sorry),
then the driver can get neccessary information from regulator
framework.
I don't think it should cause problems with multiplatform kernels.
Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures)
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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