From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 091DA337BB3 for ; Mon, 26 Jan 2026 13:05:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769432753; cv=none; b=HDRaB5AXUFuekVxKW4t7qcw1m7Lf7sa1Gcmz/DpzjacGHClS/WQGpXGsOvv1D8E38CMtG7yxj7KTa2SlCnMYHu2PkgfgW+DPaaYt3QtsCUtK9buHQz+ugDH/kMMRH7VK2TGawF1Vt96iwqWO/z15hs1Q5Mkq9CrttuGvY/9HJbY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769432753; c=relaxed/simple; bh=1Z9XYrhaHB2NNMLx9zFkQ1GYVv2k6DeBO3f12CTbexU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Be0gSjE5ugNtsImedYEgTuwA/S3PxRndCWmxVXcFbR8NMT+03r2ZYNmyNi6D1DccAU72GDinhV1txiNSwF3TevZ10zEyRHS1Vt7aVZxP9Tmv1zmA34puLB2OFRvapXI0cnOdDQqsNnJvd7jfgKoVE+CHvfJ/1sO4GGupe4pyLh4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=GQFGdFPf; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=CqYEx+EK; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GQFGdFPf"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="CqYEx+EK" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1769432740; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=U9xTs37SnhRmQ+LbBOx5D6YZCUQcOf/AW/wUxMXnN5s=; b=GQFGdFPf6lZrqzafFfPwzp+YdeGhqJ7YbAeuxzYFcEdWtZRerFGyZca6Xy+ljQt/e/ExWh aUPpI7hbCrWM6fAjtYYK1vBl+oW8wLWUjf0GsOb/wNj/MFCUKNUKavkoXRg5EeX7dkvIT4 9Dha00Wa5+WdG1lQRDFPvvKXa5yY+jY= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-553-QIfdlfwfMbOLIqqb80xV_w-1; Mon, 26 Jan 2026 08:05:39 -0500 X-MC-Unique: QIfdlfwfMbOLIqqb80xV_w-1 X-Mimecast-MFC-AGG-ID: QIfdlfwfMbOLIqqb80xV_w_1769432738 Received: by mail-wm1-f71.google.com with SMTP id 5b1f17b1804b1-4804157a3c9so48889655e9.1 for ; Mon, 26 Jan 2026 05:05:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1769432738; x=1770037538; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=U9xTs37SnhRmQ+LbBOx5D6YZCUQcOf/AW/wUxMXnN5s=; b=CqYEx+EK3fbbpRbC0KWibcwob2BJthREE2bd8/SpsatB/TgEY6ber0TmPgy+JV6bcj 3z24Ipc2eScrrSAMLx+uMuCJNjD+bA8iN6xDH2Fq4yBUjyTlyZIzz8xNbbKtPZntYReB fMRvpfbZae9LAvK37NKTm2bfsAt4sTVgsOlHSOxVh6RUWq4QJ9CcSGzK/dpQJVlDiD6d whIpyhzW3SfQbllQxvg7P4dEL3HwSkznBHOHUfpdQh2U2dWTDVMrEJ7ZhyNHrIatv9x2 PaMtdeiq0ftzkhD+e2xjgRGmFr3qWT/LSzEgxw2K3XtNXoNVVPifUW6OfJ+M1spfIg7P uFRg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769432738; x=1770037538; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=U9xTs37SnhRmQ+LbBOx5D6YZCUQcOf/AW/wUxMXnN5s=; b=qJE9M9qTbayOFTScqc7JuNx48gIXRq8oSsfq4anT9tr6NSkroqpb1UDtQwaXeoyJKG E81kRsxIfBpIEPeIw9n2zgq0+Phign1iZqUlf6BmGue7tM7MdhrhOTS5InW8cf79o0tu JqNIudwCnUz33Rdu3HYqH9k7B2/CqH4IsIGD2uPSOq4yPGI1bk6djARVVeXV1zr5Gk6y 5/JYgfhBWsYIC02MeYDgG1lOG2QoUX07geT7isfYNhrgK045gQEG9NI8DUWHrJ8pBMfd cLGOH72UadDBocPH4B6DJJAMGa0uiH3654wehLj/0D6R0x+ohktIQKST32mwJqGdtg5f sI2g== X-Forwarded-Encrypted: i=1; AJvYcCWj1bNhA24EhNaZgU8DCQfc39uBwJ0VfVHzJ0UmClvFFmcexKqu3ItfN8/X4TqYW1UCsy0sqLgj7O9UGIg=@vger.kernel.org X-Gm-Message-State: AOJu0Yy2g1UfMbuu0z46lHgWoIVYipbx8zl0Jx2wXUGZxuhcd9oXXDof inh3jSkI6/GUSNDW01+GVQYoqzJj0ap/17FWyCVCw7Mimq5KxftvZz0m+ptUDhITXAqt4m0yY5z 42PXU8/eRFyV5bqoeslO+2qXHrysXRyqOairCVinNWDARnq3Eo5W0dyXjFVWzjZBUug== X-Gm-Gg: AZuq6aILri4pQZ0joGPYYfQvfTP6Lp6zzEbujyM+bxY1pCnfy6qFgxD52mGlOJoLrVl sqB860fRnky71nvksTQGsq00lO34myfC6MdBar/zSthYDnvOok/f7W/o46C/199KTbj+GzmAHO3 V9L3RMkmoTN5pJjHTyW8K4WLy/6oNdD7Ox983lqEVPzGbMzHwF6oQU5QUiXRHYiitIa40e59SR9 GIjEY2sVgYIPHs0ewpW+o37sp58DmnsjK/fVwKm1EMzhsaLw3kjGug/dvEg+prauK3LyHvxaoGv ZmWUn3z8Y7dJBW4TMhn71mIbS/bkBmRkCPuO6Nh7+ja4tkGTuJ2rAFqIF/yVxxBLjw2YwKUF+id Sm5KXzNG80QWi39Z2yLC2S+5EPrKw63OCHpxlf05v0KeMM+2azw== X-Received: by 2002:a05:600c:5248:b0:477:5cc6:7e44 with SMTP id 5b1f17b1804b1-4805ce4e6aamr68484765e9.11.1769432738069; Mon, 26 Jan 2026 05:05:38 -0800 (PST) X-Received: by 2002:a05:600c:5248:b0:477:5cc6:7e44 with SMTP id 5b1f17b1804b1-4805ce4e6aamr68484345e9.11.1769432737470; Mon, 26 Jan 2026 05:05:37 -0800 (PST) Received: from ?IPV6:2a01:e0a:c:37e0:8998:e0cf:68cc:1b62? ([2a01:e0a:c:37e0:8998:e0cf:68cc:1b62]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4804d84ef51sm249933025e9.5.2026.01.26.05.05.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 26 Jan 2026 05:05:37 -0800 (PST) Message-ID: <286bfe2e-796e-4c71-a75c-4967450edaab@redhat.com> Date: Mon, 26 Jan 2026 14:05:36 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] vt: Add enable module parameter To: Greg Kroah-Hartman Cc: Jiri Slaby , Nicolas Pitre , Calixte Pernot , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org References: <20260126092234.713465-1-jfalempe@redhat.com> <2026012613-cotton-jellied-b67a@gregkh> <48be84fb-bee4-4a22-bde4-0d0c78282f80@redhat.com> <2026012648-vantage-mummified-2a43@gregkh> <45526d98-57b6-456e-babc-61b7331318c0@redhat.com> <2026012642-threefold-atypical-a3ad@gregkh> <99371939-e9b2-4114-8e27-e605ebf941de@redhat.com> <2026012653-designer-capably-d575@gregkh> Content-Language: en-US, fr From: Jocelyn Falempe In-Reply-To: <2026012653-designer-capably-d575@gregkh> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 26/01/2026 13:46, Greg Kroah-Hartman wrote: > 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? > It's all about the transition. Talks about VT-less system started in 2012, but since then no major desktop Linux distribution have done it. I think that one of the reason, is that if you switch off VT, of course some users will complain, as it has a lot of implications. Telling them to go rebuild their kernel is not good. Telling them to run grubby to change the kernel command line until they find alternative for their use case is better. They can experiment and do the switch when they are ready. Really it's nothing more than that. I don't think a distribution will want to maintain VT and noVT for a long time. Thanks, -- Jocelyn > thanks, > > greg k-h >