Re: GRUB2 with serial console.. please help me...

[satish kondapalli]

Hi Jordan,

In my embedded system, I dont have VGA monitor. I have only serial console.  Even after adding  serial,terminal_input/output  lines also i am not seeing any kernel log messages. 


Thanks
Sateesh.

On Sat, Apr 7, 2012 at 2:15 AM, Jordan Uggla <address@hidden> wrote:

On Sat, Apr 7, 2012 at 12:22 AM, satish kondapalli
<address@hidden> wrote:
> Hi,
>
> I am working on atom based embedded system. This Board has only serial
> port.
>
> In this board UEFI BIOS is coming up and am able to run the GRUB.EFI.   With
> below grub.cfg file, i am able to load the my kernel(this kernel has
> initramfs file system for my embedded system ) but while bootinmg the kernel
> i am not seeing any messages on serial console.  But i am seeing my menu

The fact that you're not seeing any kernel messages on the serial
console means that *the kernel* is not configured properly for serial.
All grub does is load the kernel and pass along the kernel parameters,
it doesn't parse their meaning itself. Try asking your distribution
for support on how to configure your kernel to output via serial.

> entry and the following error
> "
>
> error: no suitable mode found
> Booting however
>
> "
>
> This is my grub.cfg file:
> -----------------------------------------------------------------------------------------------------------------------
> # Boot automatically after 10 secs.
> set timeout=10
>
> # By default, boot the first entry.
> set default=0
>
> # Fallback to the second entry.
> set fallback=1
> GRUB_TERMINAL=console

GRUB_TERMINAL is a variable for configuring grub-mkconfig, and would
go in /etc/default/grub, and "console" does *not* refer to serial.
Since you're writing your grub.cfg manually and you probably want grub
to output to the screen as well as to serial I would add this to your
grub.cfg (though you might want to add more parameters to the serial
command as documented here
http://www.gnu.org/software/grub/manual/grub.html#serial ):

serial
terminal_output --append serial
terminal_input --append serial


--
Jordan Uggla (Jordan_U on irc.freenode.net)