Re: [RFC][PATCH] PM: Introduce new top level suspend and hibernationcallbacks (rev. 6)

From: Alan Stern
Date: Tue Apr 01 2008 - 16:57:15 EST


On Tue, 1 Apr 2008, Rafael J. Wysocki wrote:

> > Does ..._ext_... mean extended? (external?) If 'extended' (or if not),
> > does that imply that they're mutually exclusive alternatives for drivers
> > to use?
>
> 'ext' means 'extended'. The idea is that the 'extended' version will be used
> by bus types / driver types that don't need to implement the _noirq callbacks.

Something's wrong here. This seems to say that the "extended" version
has _fewer_ method pointers -- in which case it should be called
"restricted" instead.

> > So drivers can never validly fail to resume. That sounds fair enough. If
> > the hardware has gone away while in lower power mode (USB, say), should
> > the driver then just printk an error and return success?
>
> I think so.
>
> IMO, an error code returned by a driver's ->resume() should mean "the device
> hasn't resumed and is presumably dead". Otherwise, ->resume() should return
> success.

If the device is gone, it doesn't much matter what resume() returns.

Alan Stern

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