<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<style>P {MARGIN-TOP: 0mm; MARGIN-BOTTOM: 0mm}</style>
</head>
<body>
<div style="FONT-FAMILY: Arial; FONT-SIZE: 10pt" id="ezFormProc_div">
<div style="FONT-FAMILY: Arial" id="msgbody">
<div>
<div style="LINE-HEIGHT: 15pt">Hi, Valdis,<br>
Yes, I understand shell is a user program.</div>
<div style="LINE-HEIGHT: 15pt">I just added some uart print to see what's happening. (while trying to open a shell on LCD using USB keyboard..)</div>
<div style="LINE-HEIGHT: 15pt">When I see it n fbcon_scroll function(one of console switch functions which connect to bit blit functions)(in drivers/video/console/fbcon.c) while some printks are scrolled up on the LCD, the vc_data is using tty null (vc->port.tty->name
is null) then at some point changes to tty1. This is even when I set "console=tty0 " in the boot argument. When I set "console=tty1 ", it's the same. This is when I remvoed /etc/inittab file so that defulat inittab is put in place by busybox... I understand
busybox init starts shells on tty2,tty3,and tty4. So the output is using tty1.</div>
<div style="LINE-HEIGHT: 15pt">In input side, when I use print (to uart) on kbd_keycoad function(drivers/tty/vt/keyboard.c), and press any key, I can see the vc->port.tty->name is tty1. (vc is of type vc_data). So the input is connected to tty1 (same as output).
But I don't see any change on the LCD at that state (as I press the keyboard).</div>
<div style="LINE-HEIGHT: 15pt">Any idea? any suggestion will be appreciated. I don't know how to assign tty and how to make the fbconsole(or vc on it) to appear on the LCD so to speak.</div>
<div style="LINE-HEIGHT: 15pt">regards,</div>
<div style="LINE-HEIGHT: 15pt">Chan</div>
<div style="LINE-HEIGHT: 15pt">
<p style="MARGIN: 0cm 0cm 0pt" class="MsoPlainText"><span lang="EN-US"><font face="Courier New">_______________________________________________</font></span></p>
<p style="MARGIN: 0cm 0cm 0pt" class="MsoPlainText"><span lang="EN-US"><font face="Courier New">Kernelnewbies mailing list</font></span></p>
<p style="MARGIN: 0cm 0cm 0pt" class="MsoPlainText"><span lang="EN-US"><a href="mailto:Kernelnewbies@kernelnewbies.org"><font color="#0000ff" face="Courier New">Kernelnewbies@kernelnewbies.org</font></a></span></p>
<p style="MARGIN: 0cm 0cm 0pt" class="MsoPlainText"><span lang="EN-US"><a href="http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies"><font face="Courier New">http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies</font></a></span></p>
</div>
<div style="LINE-HEIGHT: 15pt">
<hr tabindex="-1">
</div>
<div style="LINE-HEIGHT: 15pt"><b>From : </b>"Valdis.Kletnieks@vt.edu" <Valdis.Kletnieks@vt.edu><br>
<b>Sent : </b>2014-03-12 21:14:49 ( +09:00 )<br>
<b>To : </b>Kim Chan <ckim@etri.re.kr><br>
<b>Cc : </b>Kernel <bu.kernel@gmail.com>, kernelnewbies@kernelnewbies.org <kernelnewbies@kernelnewbies.org><br>
<b>Subject : </b>Re: Does register_chrdev function make device file under /dev ?<br>
<br>
On Tue, 11 Mar 2014 08:01:26 -0000, Kim Chan said:<br>
<br>
> To my understanding, device file is needed when a user program wants to<br>
> access the device and we don't need to generate the device file for us to use<br>
> the device in kernel. Is my understanding correct?<br>
<br>
Right. You don't need to generate the device file because you shouldn't be<br>
accessing the device in a file-like manner from inside the kernel.<br>
<br>
> I am trying to open a shell on my LCD (is it going to be tty2<br>
<br>
That's userspace, not kernel access.<br>
</div>
</div>
</div>
</div>
</body>
</html>