Re: [PATCH v2 00/20] rtc: omap: fixes and power-off feature

Johan Hovold
2014-10-28T13:12:57Z

On Tue, Oct 28, 2014 at 08:47:46AM +0000, Russell King - ARM Linux wrote:
> On Tue, Oct 28, 2014 at 09:16:16AM +0100, Johan Hovold wrote:
> > It looks like we're soon to be having power-off call chains, with
> > configurable priorities, to shut of various parts of the hardware
>
> I really hope that they *don't* get used like that. I guess this is
> what happens when people don't read the code before they decide to
> implement something.
>
> All the reboot/power off/halt methods already call into the driver model,
> and the driver model then iterates over all bound drivers calling their
> "shutdown" method. So, today, as it has been for years, all device
> drivers are notified of system power off.
>
> That's where most device drivers should be cleanly stopping their
> hardware.
>
> The only thing which is left is the actual hardware triggering of the
> action, and that should be what's done via the notifier.

That's not what I was trying to refer to. But the patch set explicitly
allows for multiple, prioritised power-off handlers, which can power
off a board in different ways and with various degrees of success.
Specifically, it allows for fallback handlers in case one or more
power-off handlers fail.

So if we allow for that, what is to prevent the final power-off handler
from failing? And should this not be logged by arch code in the same way
as failure to restart is?

Johan