[U-Boot] [PATCH] README: Fix how to for serial console when CONFIG_CFB_CONSOLE is defined

[Wolfgang Denk]

Dear Fabio Estevam,

In message <1336593952-5808-1-git-send-email-fabio.estevam at freescale.com> you wrote:
> Fix how to force serial console when CONFIG_CFB_CONSOLE is defined.
> 
> Tested on a mx51evk board.
> 
> Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
> ---
>  README |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/README b/README
> index 79016e6..9fc4618 100644
> --- a/README
> +++ b/README
> @@ -615,7 +615,8 @@ The following options need to be configured:
>  
>  		When CONFIG_CFB_CONSOLE is defined, video console is
>  		default i/o. Serial console can be forced with
> -		environment 'console=serial'.
> +		by placing 'setenv("stdout", "serial");' inside
> +		board_late_init().
>  
>  		When CONFIG_SILENT_CONSOLE is defined, all console
>  		messages (by U-Boot and Linux!) can be silenced with

I think it is actually a pretty bad idea to do this.

One pretty basic rule in U-Boot is not to forcibly mess with
environment variable settings that affect operation of U-Boot when the
user might want to do things differently - otherwise we could as well
hard-code behaviour in the first place.

In this situation, no code is needed to perform such an operation.  If
you want to do this, just enable the PREBOOT feature and define a
default "preboot" command as "setenv stdout serial".  THe effect is
the same, but now the user still has a chance to change behavious as
he deems fit.

Best regards,

Wolfgang Denk

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