[syslinux] menu.c32 changes the key binding in tera term confusing user

[John Rouillard]

Hi all:

Well it looks like my declaration of having a working menu system was
a tad premature.

If I enter any of the submenu's using the enter key on my keyboard, it
selects (and runs) the first item on the submenu. If I type ^j
instead, it enters the menu and I can scroll through the options. If I
type ^M, it acts like I hit the enter key and runs the first menu
item.

Now in my terminal emulator, enter is set to send CR+LF. If I set it
to just send a CR while I am still at the boot: prompt, it is changed
to CR+LF when the menu (after typing menu.c32) is displayed. If I
change it after the menu is displayed, it seems to stay at CR (and
enter works as expected just changing to the submenu). If I type hdt
from the boot: prompt, the setting for enter is again changed to CR+LF
even though I only see:

  [ bunch of blank lines ]
  Hardware Detection Tool 0.2.5 by Erwan Velu
  CPU: Detecting
  DISKS: Detecting
  DMI: Detecting Table
  ...
  MENU: Kernel menu done (0 items)
  MENU: Summary menu done (12 items)
  MENU: Syslinux menu done (5 items)
  MENU: VESA menu done (2 items)
  MENU: About menu done (6 items)
  Starting Menu (27 menus)

and no graphics (they are displyed on the VGA monitor) on the serial
console.

So it looks like ^M or enter end up sending two characters (which
makes sense as the CR shifts to the submenu, and the LF selects the
menu item), but I am not sure why tera term is resetting it's
terminal/new-line configuration when the menu or hdt is displayed.

The enter is remapped to CR+LF even if I set default to "menu.c32"
and bypass the boot prompt.

In addition to that issue, holding down the up/down arrow keys to move
through 5 or 6 menu items seems to result in an esc being passed to
the menu system. This jumps out of the submenu or menu system. My
serial settings are: 38400,8,1,n on a directly connected serial
port. If this is a timing issue (where the multiple characters
generated by an arrow key don't arrive fast enough) I could see this
being a problem on a remote serial console where network transmision
delays may space out the bytes of the arrows.

Using ^n and ^p work ok however.

Also one additional nit, if the menu title is too long (> 55
characters or so) there doesn't appear to be any way to see the whole
line. A mention of this limitation in doc/menu.txt (or some way to
display the whole line) would be useful.

So I have workarounds for the problems, but it would be nice to remove
the surpises.

Thanks for a great tool.

--
				-- rouilj

John Rouillard
System Administrator
Renesys Corporation
603-244-9084 (cell)
603-643-9300 x 111