From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932384AbWFKBQN (ORCPT ); Sat, 10 Jun 2006 21:16:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932538AbWFKBQN (ORCPT ); Sat, 10 Jun 2006 21:16:13 -0400 Received: from py-out-1112.google.com ([64.233.166.180]:19770 "EHLO py-out-1112.google.com") by vger.kernel.org with ESMTP id S932384AbWFKBQM (ORCPT ); Sat, 10 Jun 2006 21:16:12 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding; b=IUmbsHseb0iuSquZvKNBF/NGidC1/0ahmVJa5Hze5k/Zu54Mea+1tUFq6Qnm8FXH5a5pKZg15FoVZ1DtqFvIr1n7aS4B4SVZ264UeHxhZBiRLb2E+qu/dy6zdJzfSXWmI8UgvJeZXuWZfQ1t1p6Ak75IpLLLYRAkLDFwRzXZjsY= Message-ID: <448B6ED3.5060408@gmail.com> Date: Sun, 11 Jun 2006 09:16:03 +0800 From: "Antonino A. Daplas" User-Agent: Thunderbird 1.5.0.4 (X11/20060516) MIME-Version: 1.0 To: Jon Smirl CC: Andrew Morton , Linux Fbdev development list , Linux Kernel Development , Greg KH Subject: Re: [PATCH 5/5] VT binding: Add new doc file describing the feature References: <44893407.4020507@gmail.com> <9e4733910606092253n7fe4e074xe54eaec0fe4149f3@mail.gmail.com> <448AC8BE.7090202@gmail.com> <9e4733910606100916r74615af8i34d37f323414034c@mail.gmail.com> <448B38F8.2000402@gmail.com> <9e4733910606101644j79b3d8a5ud7431564f4f42c7f@mail.gmail.com> <448B61F9.4060507@gmail.com> <9e4733910606101749r77d72a56mbcf6fb3505eb1de0@mail.gmail.com> In-Reply-To: <9e4733910606101749r77d72a56mbcf6fb3505eb1de0@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jon Smirl wrote: > On 6/10/06, Antonino A. Daplas wrote: >> > I see now that you can have tty0-7 assigned to a different console >> > driver than tty8-63. >> > Why do I want to do this? >> >> Multi-head. I can have vgacon on the primary card for tty0-7, >> fbcon on the secondary card for tty8-16. > > That's what I thought, I couldn't see any other reason. The kernel > doesn't support input from multiple users so multihead can only be > used by a single user. > > Does anyone use single user multihead on current systems? The kernel > doesn't have code in it to initialize secondary VGA cards. What modern > non-VGA hardware does this work on? matroxfb supports multihead and fbcon already has this feature for a long time, ie you can bind /dev/fb0 to tty0-3 and /dev/fb1 to tty4-6. And there are definite users because I happen to break this feature once and I got rained with complaints :-) > > If this feature doesn't work on current hardware, could it be dropped? > It would make binding to the vt system much simpler if only one driver > could be bound at a time. Anything we do to make that system simpler > would benefit everyone. You can't drop something that's already in the kernel and has users, well, the binding part at least. What we don't currently have is the fine-grained control and because of the reason's you mentioned, I said that it's for the future. (Note1: fbcon already has support to selectively bind/unbind drivers to specific tty's, using the con2fbmap utility.) So what we have is control for wholescale binding and unbinding of drivers, which essentially results in only 1 driver loaded at one time. (Note2: fbcon already has an option to determine what range of vc's to control, as a kernel boot parameter, so we can't just drop something that's already supported by one driver at least. Though I know of no one, including myself, who uses this feature.) > > At some future point I would like to explore pushing the VT system out > to user space where it becomes much easier to make it multi-user and > multi-head. If you do that, something like a single user, in-kernel > system management console makes more sense. Yes. Tony