From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Antonino A. Daplas" Subject: Re: [PATCH 5/5] VT binding: Add new doc file describing the feature Date: Sun, 11 Jun 2006 09:16:03 +0800 Message-ID: <448B6ED3.5060408@gmail.com> 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> Reply-To: linux-fbdev-devel@lists.sourceforge.net Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.92] helo=mail.sourceforge.net) by sc8-sf-list1-new.sourceforge.net with esmtp (Exim 4.43) id 1FpEYn-0003yU-RZ for linux-fbdev-devel@lists.sourceforge.net; Sat, 10 Jun 2006 18:16:13 -0700 Received: from py-out-1112.google.com ([64.233.166.178]) by mail.sourceforge.net with esmtp (Exim 4.44) id 1FpEYn-0002rq-9v for linux-fbdev-devel@lists.sourceforge.net; Sat, 10 Jun 2006 18:16:13 -0700 Received: by py-out-1112.google.com with SMTP id x31so1329789pye for ; Sat, 10 Jun 2006 18:16:11 -0700 (PDT) In-Reply-To: <9e4733910606101749r77d72a56mbcf6fb3505eb1de0@mail.gmail.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-fbdev-devel-bounces@lists.sourceforge.net Errors-To: linux-fbdev-devel-bounces@lists.sourceforge.net To: Jon Smirl Cc: Andrew Morton , Greg KH , Linux Fbdev development list , Linux Kernel Development 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