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

[Alan Stern]

On Tue, 1 Apr 2008, Benjamin Herrenschmidt wrote:

> On Tue, 2008-04-01 at 19:15 +1100, Nigel Cunningham wrote:
> > > + *   However, drivers may NOT assume anything about the availability of the
> > > + *   user space at that time and it is not correct to request firmware from
> > > + *   within @prepare() (it's too late to do that).
> > 
> > That doesn't sound good. It would be good to be able to get drivers to
> > request firmware early in the process.
> 
> Agreed. Prepare() should still allow request_firmware and full userspace
> communication / helper usage.

Pepare() is called after userspace has been frozen.  (Of course, once 
the freezer goes away this won't matter any more.)

There is a separate notifier chain which drivers can subscribe to;
notifications about impending sleeps are sent out while userspace is
still alive.  Drivers can use that for request_firmware, memory
allocation, and other things.

Alan Stern

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/