Ctrl-/ interpreted as Backspace in text console

[Liu Binsheng <liubinsheng@gmail.com>]

Hi,

When I press Ctrl-/ in the text console, it deletes a char like
backspace. But if I use Gnome and press Ctrl-/ in gnome-terminal,
Ctrl-/ behaves normally.

My laptop is ASUS A8 series. It uses a normal keyboard.
 
I've installed console-setup, and these are the valid lines in
/etc/default/keyboard:

XKBMODEL="asus_laptop"
XKBLAYOUT="us"
XKBVARIANT=""
XKBOPTIONS="ctrl:nocaps"
BACKSPACE="guess"

Here's the results of running `showkey -a` in text console:

Press any keys - Ctrl-D will terminate this program

^? 	127 0177 0x7f		> when pressing Ctrl-/
^? 	127 0177 0x7f		> when pressing Backspace
/ 	 47 0057 0x2f		> when pressing /
? 	 63 0077 0x3f		> when pressing ?
^D 	  4 0004 0x04		> Ctrl-D

The results of running `showkey -a` in gnome-terminal:

Press any keys - Ctrl-D will terminate this program

^_ 	 31 0037 0x1f		> when pressing Ctrl-/. result differs
^? 	127 0177 0x7f		> when pressing Backspace
/ 	 47 0057 0x2f		> when pressing /
? 	 63 0077 0x3f		> when pressing ?
^D 	  4 0004 0x04		> Ctrl-D

This problem is very annoying because I bind Ctrl-/ to undo in
emacs. Could you please provide any suggestions to make Ctrl-/ not
behave like backspace?
-- 
Liu Binsheng <liubinsheng@gmail.com>