From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Antonino A. Daplas" Subject: Re: [PATCH 0/7] Detaching fbcon Date: Wed, 07 Jun 2006 07:17:18 +0800 Message-ID: <44860CFE.2060908@gmail.com> References: <44856223.9010606@gmail.com> <9e4733910606060910m44cd4edfs8155c1fe031b37fe@mail.gmail.com> <9e4733910606060919p2a137e07wd58b51a227f5aa5e@mail.gmail.com> <4485DB6C.704@gmail.com> <9e4733910606061400i172d20a7qa9583b9b9245f6f9@mail.gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <9e4733910606061400i172d20a7qa9583b9b9245f6f9@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: Cc: Andrew Morton , Linux Fbdev development list , Linux Kernel Development Jon Smirl wrote: > On 6/6/06, Antonino A. Daplas wrote: >> Jon Smirl wrote: >> > On 6/6/06, Jon Smirl wrote: >> >> On 6/6/06, Antonino A. Daplas wrote: >> >> > Overall, this feature is a great help for developers working in the >> >> > framebuffer or console layer. There is not need to continually >> >> reboot the >> >> > kernel for every small change. It is also useful for regular users >> >> who wants >> >> > to choose between a graphical console or a text console without >> >> having to >> >> > reboot. >> >> >> >> Instead of the sysfs attribute, what about creating a new escape >> >> sequence that you send to the console system to detach? Doing it that >> >> way would make more sense from a stacking order. It just seems >> >> backwards to me that you ask a lower layer to detach from the layer >> >> above it. The escape sequence would also work for any console >> >> implementation, not just fbcon. >> >> >> >> If console detached this way and there was nothing to fallback to >> >> (systems without VGAcon), it would know not to try and print anything >> >> until something reattaches to it. >> > >> > Another thought, controlling whether console is attached or not is an >> > attribute of console, not of fbcon. >> >> If the console attached fbcon, then I agree that console should decide >> when to detach fbcon. But that's not what happens, it's fbcon that >> attaches itself. >> >> It's not that you're wrong, it's just how the current vt/console layer >> works. If someone do decide to add this feature to the vt/console layer, >> then I'm more than willing to have fbcon support that as well. > > This is just kind of twisted since console increments the fbcon ref > count. Oh, the console and vt layer is exactly that, twisted :-) > Is /dev/console a real device, it that where the sysfs > attribute should go? We have /sys/class/tty/console. > How is the stack maintained of what was previously bound to console? That's the problem, there is no stack. Once a driver binds to a console, the previous driver is lost. > What if I unbind fbcon on a system that doesn't have VGAcon for a backup? All systems have a backup console, otherwise you're system won't boot. It's either vgacon or dummycon. Tony Tony