Subject: Re: [RFC] b43: rework rfkill code
From: Johannes Berg <johannes@sipsolutions.net>
To: Michael Buesch <mb@bu3sch.de>
Cc: Marcel Holtmann <marcel@holtmann.org>,
	Matthew Garrett <mjg59@srcf.ucam.org>,
	linux-wireless@vger.kernel.org, bcm43xx-dev@lists.berlios.de,
	hmh@hmh.eng.br
In-Reply-To: <200812101831.13526.mb@bu3sch.de>
References: <20081210150935.GA10927@srcf.ucam.org>
	 <1228929529.15837.34.camel@johannes.berg>
	 <1228929820.15837.40.camel@johannes.berg> <200812101831.13526.mb@bu3sch.de>
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Date: Wed, 10 Dec 2008 18:37:23 +0100
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On Wed, 2008-12-10 at 18:31 +0100, Michael Buesch wrote:

> I introduced it when I ported b43 to rfkill.
> Well, a lot of semantical changes were made _after_ that.
> When I added it there only were two rfkill states and b43 handled these w=
rt the
> actual hardware state (and I still think that's the right thing to do. Th=
e sw-state intermix
> is confusing).

Right.

> So when I added the flag it meant:
> user_claim_unsupported =3D True means user cannot change the hardware kil=
l state.

Yeah, but the assumption that software can change the "hardware kill
state" is rather stupid to start with, I think.

> So basically it means the device has two states. One software state and o=
ne hardware
> state.
> However, I don't know what the semantics for the flag are today. Lots of =
code changed.

Ok. I think the fundamental flaw here is assuming that there's just a
single state. There isn't. The device can be turned off in hardware (in
which case sw won't be able do anything about it, but we want to know)
or in software (which we want to handle). Pretending that there's just a
single state that's either hw-off, sw-off or on is plain wrong. The
device can be hw-off and sw-off at the same time, and then if you turn
off the hw-off button it won't turn on (however, unless your system
integrator totally screwed up, you won't have a hw and a sw button on
your system)

johannes

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