Re: [PATCH 0/8] Suspend block api (version 8)

Igor Stoppa
2010-05-27T12:28:07Z

ext Florian Mickler wrote:

>
> Converting a driver to using any constraint-API would require analysing
> what makes a driver refuse suspending in the old suspend handler and
> then specify any "no suspend" (or whatever) constraint before those
> conditions arise and clearing of the constraints when it is no longer critical.
> (Much work.)
>

That's not really true.
Nothing prevents using from the beginning a sane approach where drivers
are required to specify constraints.

The way it has been done for the N900 was to let driver developers
specify _very_ conservative constraints, during the conversion phase.

Then each driver has been optimized.

If you have as requirement for driver developers that their driver must
be working properly when compiled as module, it is possible to test the
system with a minimalistic kernel which enters the lowest power state as
soon as possible, plus only those modules that are being optimized.

This allows also to identify parasitic drivers, which fail to apply the
proper constraint and instead rely on some other driver to keep the
system alive.

igor