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From: Arnd Bergmann <arnd@arndb.de>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: [PATCH 5/9] mfd: Add UART support for the ST-Ericsson CG2900.
Date: Sat, 30 Oct 2010 02:01:01 +0200
Cc: "Par-Gunnar Hjalmdahl" <pghatwork@gmail.com>,
	linus.walleij@stericsson.com, linux-bluetooth@vger.kernel.org,
	linux-kernel@vger.kernel.org, Lukasz.Rymanowski@tieto.com
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On Friday 29 October 2010, Alan Cox wrote:

> > line discipline then even though that could cause other problems. I do
> > not know if it is possible to add a condition in Kconfig otherwise so
> > the CG2900 ldisc cannot be active while the "normal" ldisc driver is
> > selected.
> 
> Not sure I follow the concern here ?

It's about the ldisc number. Both bluetooth and cg2900 register themselves
to ldisc 15 (N_HCI). A user doing TIOCSETD can only get one of the two.

The solution would not be to make the two ldisc implementations mutually
exclusive, but to make cg2900 use a new ldisc number, e.g. N_HCI_CG2900.
However, I'm still not convinced that this is actually necessary, we might
be able to add hooks into the existing N_HCI implementation for the
extensions in cg2900.

	Arnd