Re: [PATCH] tty: Added a CONFIG_TTY option to allow removal of TTY

[Josh Triplett <josh@joshtriplett.org>]

On Fri, Aug 24, 2012 at 02:15:37PM +0100, Alan Cox wrote:
> On Thu, 23 Aug 2012 18:14:48 -0700
> Joe Millenbach <jmillenbach@gmail.com> wrote:
> > On Tue, Aug 21, 2012 at 6:20 AM, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> > >
> > > ...
> > >
> > > >  config MOUSE_PS2
> > > >       tristate "PS/2 mouse"
> > > > +     depends on TTY
> > >
> > > It shouldn't. It would be good to understand why this occurs.
> > 
> > 
> > If I enable this config option, and turn off TTY I get the below errors.
> > 
> > drivers/built-in.o: In function `serport_ldisc_read':
> > serport.c:(.text+0x1aace6): undefined reference to `tty_name'
> > serport.c:(.text+0x1aad57): undefined reference to `tty_name'
> > drivers/built-in.o: In function `serport_init':
> > serport.c:(.init.text+0x8478): undefined reference to `tty_register_ldisc'
> > drivers/built-in.o: In function `serport_exit':
> > serport.c:(.exit.text+0xb29): undefined reference to `tty_unregister_ldisc'
> > 
> > All because MOUSE_PS2 depends on SERIO, just like a lot of entries I
> > blocked.  I assume this means I should keep the dependency on TTY.
> > Unfortunately, I don't have time to dig deeper for the true cause of the
> > dependency right now.
> 
> The true cause I think is that serio/serport.c should depend on tty to be
> built but the ps/2 mouse bits shouldn't.

On the other hand, most people disabling CONFIG_TTY will be building an
extreme embedded system, and on such a system a PS/2 mouse seems highly
unlikely.  Given that, perhaps the goal of removing dependencies on TTY
could happen incrementally once CONFIG_TTY exists?

- Josh Triplett