[U-Boot] [PATCH] README: Fix how to for serial console when CONFIG_CFB_CONSOLE is defined
Fix how to force serial console when CONFIG_CFB_CONSOLE is defined.
Tested on a mx51evk board.
Signed-off-by: Fabio Estevam fabio.estevam@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
Dear Fabio Estevam,
In message 1336593952-5808-1-git-send-email-fabio.estevam@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@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");' insideboard_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
Hi Wolfgang,
On Sun, May 20, 2012 at 4:13 PM, Wolfgang Denk wd@denx.de wrote:
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.
I tried the "no code" approach initially (following the README) and it did not allow me to redirect the console output to serial port.
Only when I placed 'setenv("stdout", "serial");' inside board_late_init() worked for me.
Regards,
Fabio Estevam
Dear Fabio Estevam,
In message CAOMZO5AieZMn1d0LiE6Kd3o8KdHxE1_s80REqzAXyCcQWtGJEA@mail.gmail.com you wrote:
I tried the "no code" approach initially (following the README) and it did not allow me to redirect the console output to serial port.
Did you try the approach I just described? I have used this for many years on several boards (although I did not test it recently).
Best regards,
Wolfgang Denk
participants (3)
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Fabio Estevam -
Fabio Estevam -
Wolfgang Denk