From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by befuddled.reisers.ca (Postfix, from userid 65534) id DDF9F1EF69C; Thu, 26 Jun 2014 17:48:38 -0400 (EDT) Received: from mta1.math.wisc.edu (mta1.math.wisc.edu [144.92.166.23]) by befuddled.reisers.ca (Postfix) with ESMTP id 52A791EF516 for ; Thu, 26 Jun 2014 17:48:37 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mta1.math.wisc.edu (Postfix) with ESMTP id D39EB388865 for ; Thu, 26 Jun 2014 16:48:35 -0500 (CDT) Received: from mta1.math.wisc.edu ([127.0.0.1]) by localhost (mta1.math.wisc.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id WhTsPz7Z-W5A for ; Thu, 26 Jun 2014 16:48:35 -0500 (CDT) Received: from mta1.math.wisc.edu (localhost [127.0.0.1]) by mta1.math.wisc.edu (Postfix) with ESMTP id A18B6388835 for ; Thu, 26 Jun 2014 16:48:34 -0500 (CDT) X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on mta1.math.wisc.edu X-Spam-Level: X-Spam-Status: No, score=-102.5 required=6.5 tests=ALL_TRUSTED,BAYES_00, USER_IN_WHITELIST autolearn=disabled version=3.3.2 Received: from mailhost.math.wisc.edu (erdos.math.wisc.edu [144.92.166.25]) by mta1.math.wisc.edu (Postfix) with ESMTP for ; Thu, 26 Jun 2014 16:48:34 -0500 (CDT) Received: from [144.92.166.19] (vv507j.math.wisc.edu [144.92.166.19]) (using TLSv1 with cipher ECDHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by mailhost.math.wisc.edu (Postfix) with ESMTPSA id 9F17D42066C for ; Thu, 26 Jun 2014 16:48:34 -0500 (CDT) Message-ID: <53AC9533.3010906@math.wisc.edu> Date: Thu, 26 Jun 2014 16:48:35 -0500 From: "John G. Heim" Organization: University of Wisconsin-Madison User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: "Speakup is a screen review system for Linux." Subject: Re: slackware on a very fast machine References: <53AC736D.3050405@math.wisc.edu> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 X-BeenThere: speakup@linux-speakup.org X-Mailman-Version: 2.1.16 Precedence: list Reply-To: "Speakup is a screen review system for Linux." List-Id: "Speakup is a screen review system for Linux." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 26 Jun 2014 21:48:39 -0000 The serial consoles you are talking about run in what's called user space. When you connect to a serial console, you're actually talking to a server process called getty or agetty. It's not that different from a web server or ssh server. The kernel doesn't know or care about those processes. Accessing the serial port in a kernel module is a totally different process. Of course, you may be saying, "Ah, but I can set up a serial console in the kernel". And this is correct. But that console stops working once the kernel is booted and if you want to continue to use a console on that same serial port you have to set up a getty. If you have a terminal or terminal emulator listening on ttyS0, it may appear to be seamless but it's actually switching from kernel output to a getty. So now maybe you are asking why can't speakup just access the serial port the same way as the kernel serial console? And that I don't know. I suspect that code doesn't do things the "right way" either. The speakup code talks directly to the serial port at address 3F8. you're not supposed to do that. First it calls a function that is part of the regular kernel code that appears to do nothing except return an error code. Upon getting that error code, the speakup code errors out. All you have to do to make it work is comment out the part where the speakup code errors out. But my patch removes the call to the stupid/crazy function as well. That function cannot return a success, so why call it? It's crazy. It makes no sense what so ever. I've asked twice on the kernel mailing list what the speakup code should do instead and got nothing but static. All the answers I got either made no sense or they suggested rewriting the speakup code so that it would run in user space. But that would make it practically useless. The beauty of speakup is that you can get boot messages with it. I was so angry at one point I considered contacting a lawyer. What I really should do is find out how the kernel serial console does it. I'll bet it reads/writes directly to 0x3F8 as well. In that case, the linux kernel developers are discriminating against speakup. The problem doesn't really even effect me that much. I can easily just recompile the kernel. I've got my version of the debian wheezy kernel on about 200 amachines here in my department. But if I have to use grml, I can't use my litetalk. On 06/26/14 15:02, Rob Hudson wrote: > I don't understand why the kernel has serial bugs. Many many many > companies still use serial consoles, and in fact, as faras I know, it is > still the most common way of interacting directly with rack-mounted > computers and some high end routers. What's the deal? > ----- Original Message ----- From: "John G. Heim" > To: "Speakup is a screen review system for Linux." > > Sent: Thursday, June 26, 2014 2:24 PM > Subject: Re: slackware on a very fast machine > > >> The syntax is "modprobe speakup_ltlk". >> >> But it isn't going to help unless slackware hacked the kernel clode >> to fix the serial port bug. If they used the speakup code as it is in >> the kernel, your litetalk won't work. >> I started trying to make a fork of grml with a patched kernel but >> never had the time to really get into it. Instead I've been using an >> FAI disk. FAI is actually an installer system. FAI stands for fully >> automated install. But they make it real easy to create a live CD. >> On 06/26/14 14:12, Jude DaShiell wrote: >>> I can't determine when the 10 seconds starts or ends with >>> slackware-Current on this machine since the machine appears to be >>> running >>> too fast to get any usable audible indicators from it any longer. >>> What is >>> the correct syntax to modprobe speakup and have speakup come up on a >>> litetalk synthesizer on ttyS0? I might be able to get slackware to run >>> the speakup.s kernel and if I can do that, I ought to be able to key the >>> modprobe line in once I get in as root. >>> >>> >>> >>> jude >>> >>> _______________________________________________ >>> Speakup mailing list >>> Speakup@linux-speakup.org >>> http://linux-speakup.org/cgi-bin/mailman/listinfo/speakup >>> >> >> -- >> --- >> John G. Heim, 608-263-4189, jheim@math.wisc.edu >> _______________________________________________ >> Speakup mailing list >> Speakup@linux-speakup.org >> http://linux-speakup.org/cgi-bin/mailman/listinfo/speakup >> > > _______________________________________________ > Speakup mailing list > Speakup@linux-speakup.org > http://linux-speakup.org/cgi-bin/mailman/listinfo/speakup -- --- John G. Heim, 608-263-4189, jheim@math.wisc.edu