Re: [RFD] How to tell ACPI drivers what the target sleep state is (was: Re: [PATCH 1/2] acpi choose sleep state help)

On Thursday, 21 June 2007 17:37, David Brownell wrote:

quoted

quoted

IMO it can be done in two different ways:
1) via a .suspend() argument
2) via a global variable that the drivers can read.

For sufficiently small values of "two" that is.  

Other solutions that have been described on the PM list include

  3) Providing accessors to the information actually needed
     in drivers ... e.g. say whether this clock or power domain
     will be available in that target state.

Well, you need to store that information somewhere.  The way in which
it will be provided to drivers is a secondary thing.

To me, the most important question is whether we want to pass that information
as a .suspend() argument or in any different way, which involves the use of a
global variable (or a set of variables) and that's 2).

  4) Act more like "current" ... there's a function returning
     whatever "state" struct is settled on.  (But ideally
     without the pseudo-global.)

How would you be going to arrange that in practice?

I'm amused that nobody really reacted to the technical comments in
my previous posts on this thread.  That's unfortunate, since from
where I sit it feels to me like everyone else is a johnny-come-lately
on this issue, and is now grasping at the quickest and dirtiest ways
to work around the issue instead of coming to grasp with the various
underlying issues.

IMO #3 is strongly preferable.

Of course we can do that.  At least I don't have any objections.

Greetings,
Rafael


-- 
"Premature optimization is the root of all evil." - Donald Knuth