[syslinux] boot... round 2

[poma]

On 30.06.2015 10:12, poma wrote:
> 
> With this config:
> $ head -n2 isolinux/isolinux.cfg 
> serial 0 9600
> default vesamenu.c32
> 
> via the "Raw File Port Mode - VirtualBox"
> 
> I got this:
> $ file /tmp/serial0.txt 
> /tmp/serial0.txt: empty
> 
> 
> For the kernel log this in turn works OK:
> console=ttyS0 console=tty0 ignore_loglevel
> 
> 
> Is it really needed, exclusively a physical serial connection for the isolinux debug?
> 
> 

Actually, ISOLINUX's "serial" directive works quite OK for both,
VirtualBox and Virtual Machine Manager(virt-manager).

virt-manager config example:

- Serial Device 1 (Primary Console)
   Device type: file
   Source path: /tmp/serial0.txt

- Serial Device 1 (Primary Console)
   Device type: pty
   Source path: -


$ head -n3 isolinux/isolinux.cfg 

serial 0
default vesamenu.c32

~~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~ ~~~~~~~ ~~~~~~ ~~~~~ ~~~~ ~~~ ~~ ~

But the question remains, what do we achieve with all these "serial" "thing"?

With a broken ISOLINUX v6, no data flow into serial console.
With those functional - ISOLINUX v4 and v5, in this case, a menu is displayed.

What's the point in:
"A real serial port that can reliably operate at 115200 8n1 may be
necessary."

Gene, is there something special in "A real serial port" usage, compared to emulated?

~~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~ ~~~~~~~ ~~~~~~ ~~~~~ ~~~~ ~~~ ~~ ~

If someone wants to play with this on Fedora, set it this way:

'live.py' is the 'isolinux.cfg' generator

$ rpm -qf /usr/lib/python2.7/site-packages/imgcreate/live.py
python-imgcreate-23.1-2.fc23.x86_64


$ su
# cd /usr/lib/python2.7/site-packages/imgcreate/

# cp live.py live.py.bkp

Switch to 'isolinux-debug.bin' usage
&
append the "serial 0" directive at the top of the 'isolinux.cfg'

# sed -i 's/isolinux.bin/isolinux-debug.bin/' live.py
# sed -i '/default %/ i\serial 0' live.py


Ref.
http://www.tldp.org/HOWTO/Remote-Serial-Console-HOWTO/configure-boot-loader-syslinux.html