Re: Nested suspends; messages vs. states

Benjamin Herrenschmidt
2005-03-24T05:03:10Z

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On Wed, 2005-03-23 at 18:45 -0800, David Brownell wrote:

> If you've hogtied your system by forcing some devices ("busses") into
> certain states that prevent others from working, it seems only fair to
> me that it stay hogtied.

No. For example, I'm a host controller. I notice I didn't get any
request for a while, I want to enter a suspended state. That means going
through dependencies of my childs so they can all enter a state
compatible with me going to suspend.

> I suspect you're actually agreeing with me there that some of the
> drivers need flexibility to manage their power states. And maybe
> even that such modes will be the main ones of interest...
>
> My answer to the question of how those parent/child dependency
> details should be managed was to ensure that the parent can do
> what it needs to. That is, decentralize those issues. I don't
> understand why you seem to dislike that approach, when so many
> of your examples seem to confirm it would work.

I want to have the driver in control, yes. But I also want to have a
core that removes the burden from driver writers in the "generic" cases.
It's all a tradeoff to find :)