From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from viefep16-int.chello.at (viefep16-int.chello.at [213.46.255.17]) by dsl2.external.hp.com (Postfix) with ESMTP id 455864829 for ; Tue, 1 Apr 2003 12:27:35 -0700 (MST) Message-ID: <3E89E824.8020404@gmx.at> Date: Tue, 01 Apr 2003 21:27:32 +0200 From: Christoph Plattner MIME-Version: 1.0 To: knaresh@india.hp.com Cc: parisc-linux@lists.parisc-linux.org Subject: Re: [parisc-linux] PDC console problem. References: <3E89DBF4.102AC68A@india.hp.com> Content-Type: text/plain; charset=us-ascii; format=flowed Sender: parisc-linux-admin@lists.parisc-linux.org Errors-To: parisc-linux-admin@lists.parisc-linux.org List-Help: List-Post: List-Subscribe: , List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: Hello again! There are two drivers, but they depend. Int arch/parisc/kernel driver implements the kernel "printk()" (the internal kernel console). This driver has NO device name, as it cannot be access as /dev/ttyB0. BUT: This driver is register under the name "ttyB0" to be selected as preferred device on the kernel paramter line with "console=ttyB0". The drivers/char driver is the full PDC serial console driver as a TTY driver (like all the other serial drivers). This driver is registers as MAJOR 11, MINOR 0 driver in the TTY interface and supports fully TTY functionality (althogh some routines are dummy, e.g. you cannot change the BAUD RATE, etc...). The low lever routione (printing out a character, polling the keyboard) are implemented in the first mentioned driver.. The third driver play a role is the "/dev/console" tty driver, which assosiates the two drivers above as console driver. So the kernel paramter line also assigns the "/dev/ttyB0" as the driver behind the "/dev/console". And this driver is running bidirectional. So commig to your simulator. I do not know this, but perhaps you have simple a problem with the timing here. My PDC console drive is in opposite to other typical TTY drivers running in POLLING mode. The PDC interface does not support a interrupt-like handling. So the PDC driver polls all 30ms (as far as I remember) if a key was pressed on the PDC console. My be, the time progress has other properties on the simulator .... Christoph Naresh wrote: > Hi, > > I am trying to boot PA-Linux off a PA-RISC simulator. I am facing a > problem with the PDC console. On my first attempt, I saw the message > asking me to switch the console. So I turned the PDC console config > option on ( the serial mux option was turned off). I added the parameter > 'console=ttyB0' in 'palo.conf'. I created the device file '/dev/ttyB0' > with major/minor = 11/0 on my ramdisk. With this, the kernel boots up on > the simulator all the way upto the sash ( Stand-alone shell) prompt. I > can even see the prompt. But, the problem is that this console doesnt > seem to be accepting input from the keyboard. It is kind of like in a > locked state. > > I was going through some of the FAQ and the mailing list archive and > understand that the PDC console is not a full blown console and can only > display output. Is is true that the PDC console cannot accept keyboard > input? Or am I missing something? > > I also see that there are 2 versions of the PDC console driver : > 'arch/parisc/kernel/pdc_cons.c' and 'drivers/char/pdc_console.c'. Both > use the device ttyB. From what I understand, the former is used before > any of the serial drivers are initialized during boot, and has only > write capability. The latter is the full-blown console driver (though I > am not sure if it has write capability). Is my understanding correct? > > I am using the source tarball 'palo-latest.tar.gz' from the parisc-linux > cvs respository and cross-compiling this on an x86 box. > > Regards, > Naresh. > > PS: My "init" process is 'sash' and I also have a '/dev/console' device > ( major=5 minor=1) on my ramdisk. The Serial driver config option is on > and I can see it being initialized in the boot path after the PDC > console. > > _______________________________________________ > parisc-linux mailing list > parisc-linux@lists.parisc-linux.org > http://lists.parisc-linux.org/mailman/listinfo/parisc-linux > > -- ------------------------------------------------------- private: christoph.plattner@gmx.at company: christoph.plattner@alcatel.at