[syslinux] escape char clutter makes prompt unreadable

[H. Peter Anvin]

Jim Cromie wrote:
> hey folks,
> 
> Im using pxelinux to boot a Soekris box (which works fine to a default 
> image)
> 
> Ive added a bunch of LABEL, KERNEL pairs,
> but I cant read the display; Im buried in escape codes.
> 
> Ive captured some of it to a typescript file:
> it starts out kosher, but goes unreadable rather quickly,
> 
> 0005520                                          \r   T   F   T   P   .
> 0005540   /  \b  \r
> 0005560
> *
> 0005660          \r  \r
> 0005700
> *
> 0006000              \r 033   [   G   3   ;   0   1   H 033   [   G   3
> 0006020   ;   9   7   H 033   [   s   P 033   [   u 033   [   G   3   ;
> 0006040   0   1   H 033   [   s   X 033   [   u 033   [   G   3   ;   0
> 0006060   1   H 033   [   s   E 033   [   u 033   [   G   3   ;   0   1
> 0006100   H 033   [   s   L 033   [   u 033   [   G   3   ;   0   1   H
> 0006120 033   [   s   I 033   [   u 033   [   G   3   ;   0   1   H 033
> 0006140   [   s   N 033   [   u 033   [   G   3   ;   0   1   H 033   [
> 0006160   s   U 033   [   u 033   [   G   3   ;   0   1   H 033   [   s
> 0006200   X 033   [   u 033   [   G   3   ;   0   1   H 033   [   s
> 0006220 033   [   u 033   [   G   3   ;   0   1   H 033   [   s   2 033
> 
> 
> I upgraded to pxelinux 2.11 just to be sure, same results.
> 

You have serial redirection enabled in your BIOS.  Serial redirection uses 
ANSI/VT escape codes to mimic the display.  Apparently picocom doesn't handle 
that.

> Less related:
> LILO gives me some display issues too; it doubles the chars,
> so 2.6.8 label looks like 22..66..88, and it fouls up newlines.

This is because you have serial port redirection enabled in the BIOS, *AND* 
serial console enabled in LILO.  The two make a bad mix.

	-hpa