CONFIG_DUMMY_CONSOLE question

CONFIG_DUMMY_CONSOLE question

[alebas]

Hi all,

Checking console initialization on mpc8272ads board,
I have seen that the CONFIG_DUMMY_CONSOLE config
parameter is allways set in root .config file, regardless
of its value on my arch/ppc/configs/ads8272_defconfig file.

This parameter drives to the VGA dummy console being
compiled and included in the vmlinux binary, and started
as default console for the board (which must be changed
with console boot arg).

Does anyone knows if this parameter is a must in any kernel
2.6 configuration? And why? Can it be removed, as my board
doesn't use VGA at all? How? (I have tried several options)

Thanks,

Alex

Re: CONFIG_DUMMY_CONSOLE question

[Tom Rini]

On Thu, Dec 09, 2004 at 10:54:15AM +0100, alebas@televes.com wrote:

> Hi all,
> 
> Checking console initialization on mpc8272ads board,
> I have seen that the CONFIG_DUMMY_CONSOLE config
> parameter is allways set in root .config file, regardless
> of its value on my arch/ppc/configs/ads8272_defconfig file.
> 
> This parameter drives to the VGA dummy console being
> compiled and included in the vmlinux binary, and started
> as default console for the board (which must be changed
> with console boot arg).
> 
> Does anyone knows if this parameter is a must in any kernel
> 2.6 configuration? And why? Can it be removed, as my board
> doesn't use VGA at all? How? (I have tried several options)

It's not a "dummy" VGA console, it's a "dummy" console.  IIRC, this is
selected with CONFIG_VT (or is it CONFIG_VT_CONSOLE?).  IIRC, the real
problem is that when you have dummy console, it steals the console even
if you would have had console on some sort of serial port.

The bottom line is that if you don't have some sort of video device,
just disable CONFIG_VT.

-- 
Tom Rini
http://gate.crashing.org/~trini/

Re: CONFIG_DUMMY_CONSOLE question

[alebas]

Tom Rini <trini@kernel.crashing.org> wrote:

> It's not a "dummy" VGA console, it's a "dummy" console.  IIRC, this is
> selected with CONFIG_VT (or is it CONFIG_VT_CONSOLE?).  IIRC, the real
> problem is that when you have dummy console, it steals the console even
> if you would have had console on some sort of serial port.
>
> The bottom line is that if you don't have some sort of video device,
> just disable CONFIG_VT.
>

Thanks. Finally your clue guided me to the problem. All those configs
(CONFIG_VT, CONFIG_VT_CONSOLE, CONFIG_DUMMY_CONSOLE, etc) defaults to Y
when CONFIG_EMBEDDED is not set. I was working with this option unset
(accidentally), so this was the problem.

Alex

P.S. CONFIG_DUMMY_CONSOLE is selected only if CONFIG_VGA_CONSOLE is
not set. That's why I had called it "dummy vga console". sorry about
the confusion.