linux-kernel - Re: [PATCH] vt: Add enable module parameter

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Message-ID: <2026012653-designer-capably-d575@gregkh>
Date: Mon, 26 Jan 2026 13:46:13 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: Jocelyn Falempe <jfalempe@...hat.com>
Cc: Jiri Slaby <jirislaby@...nel.org>, Nicolas Pitre <npitre@...libre.com>,
	Calixte Pernot <calixte.pernot@...noble-inp.org>,
	linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org
Subject: Re: [PATCH] vt: Add enable module parameter

On Mon, Jan 26, 2026 at 01:26:34PM +0100, Jocelyn Falempe wrote:
> On 26/01/2026 11:59, Greg Kroah-Hartman wrote:
> > On Mon, Jan 26, 2026 at 11:48:50AM +0100, Jocelyn Falempe wrote:
> > > On 26/01/2026 11:20, Greg Kroah-Hartman wrote:
> > > > On Mon, Jan 26, 2026 at 10:43:35AM +0100, Jocelyn Falempe wrote:
> > > > > On 26/01/2026 10:33, Greg Kroah-Hartman wrote:
> > > > > > On Mon, Jan 26, 2026 at 10:21:50AM +0100, Jocelyn Falempe wrote:
> > > > > > > This allows to build the kernel with CONFIG_VT enabled, and choose
> > > > > > > on the kernel command line to enable it or not.
> > > > > > 
> > > > > > This says what is happening, but not why?
> > > > > > 
> > > > > > > Add vt.enable=1 to force enable, or vt.enable=0 to force disable.
> > > > > > 
> > > > > > Why are we using a 1990's technology for a new feature?  What is this
> > > > > > going to allow to have happen?  Who needs/wants this?  Who will use it?
> > > > > > For what?
> > > > > 
> > > > > The goal is to ease the transition to disable CONFIG_VT.
> > > > > 
> > > > > So if this is merged, you can boot without VT on any Linux distribution,
> > > > > without rebuilding the kernel.
> > > > 
> > > > But that's a distro-specific thing, the distro should be enabling or
> > > > disabling the option as it needs, it should not be a user-configurable
> > > > boot-time selection option as userspace depends entirely on this either
> > > > being there or not.  Why would you have a kernel with both options but
> > > > userspace without that?
> > > 
> > > Actually the userspace side works with or without VT, at least with Fedora,
> > > I've my Gnome session in both cases.
> > 
> > Great!  Then why is this even needed?  Who wants such a "let's not make
> > up our mind until we boot" type of system?
> > 
> > Given that traditionally the command line is a "secure" thing, that is
> > locked down by distros and orginizations, who would ever be able to be
> > changing this type of thing?  Who would want to support userspace that
> > handles both at the same time?
> > 
> > I don't see the issue here, if a distro doesn't want to support VT, then
> > disable it in the kernel and all is good.  If they do want to support
> > it, than enable it.  Don't do both :)
> 
> Maybe the real issue is that VT cannot be built as a module.
> That way the userspace would be able to load it only if it needs it.
> 
> That's probably more complex than my 3 lines patch, but I can try.
> Would you prefer it that way?

If that would make it simpler for a distro to handle this, perhaps.  Try
it and see, I think the last time this came up, unwinding this into a
module just wasn't possible, but that might have been a long time ago, I
can't recall.

But again, why wouldn't a distro pick a "this is what we are going to
support" line and stick with it?  Why would they want to support both?

thanks,

greg k-h