Re: Non-enumerable devices on USB and other enumerable buses

From: Mark Brown
Date: Wed Aug 14 2013 - 11:39:50 EST

On Wed, Aug 14, 2013 at 10:27:26AM -0400, Alan Stern wrote:
> On Wed, 14 Aug 2013, Mark Brown wrote:

> > I'd expect that we're just looking at hooks around connection and
> > disconnection here here - if we're looking at much more it seems like we
> > must be doing something wrong.

> Connection and disconnection of what?

The device on the bus.

> In the example mentioned earlier, the GPIOs to power an on-board USB
> hub would have to be initialized when the host controller was started.
> You wouldn't want to wait for the on-board hub to be detected, because
> without those GPIOs set properly, it never would be discovered on the
> USB bus. Right?

Yes, so you'd want callbacks when the device actually appears and

> Perhaps the platform-level code would need to hook into the places
> where the discoverable bus is registered and unregistered.

We'd need some way to get information to the drivers still, and to
handle drivers that want to stop and start things.

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