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List:       linux-power
Subject:    Re: [linux-power] Re: [Linux-pm-devel] Updated PM Scheme
From:       "Stephen C. Tweedie" <sct () redhat ! com>
Date:       2001-04-23 10:14:53
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Hi,

On Sun, Apr 22, 2001 at 11:58:49AM -0700, Patrick Mochel wrote:
> > Well, I'd rather have a single entry point of kind "notifier" that gets
> > passed a message than several functions.
> > 
> > First, it makes it easier to implement for drivers that don't need to
> > handle all of the requests (I have several examples in mind of drivers
> > that don't need the "early" call to alloc memory for example).
> 
> I thought about that and decided against it, and this is why; In that
> scenario, the driver handler has a big switch statement. It either
> implements the functionality in the switch statement, or calls a function
> for each of the different messages.

You often have a lot of common code between the paths, though --- an
ide driver might do a mapping from the device struct to an ide_drive_t
before dispatching the appropriate function, for example, or might
take a set of driver locks before starting the operation.  It's easier
to do that with a single notifier.

--Stephen

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