Why doesn't U-Boot disable the console output

Question

I have this system which is accessed by a serial Debug Port. I want to disable all of the output, that was made during the U-Boot boot. Therefore there is the

setenv silent 1

parameter, which i put into the BOOTCMD string like:

#define CONFIG_BOOTCOMMAND " setenv silent 1;" \

"bootm "

and there is the

#define CONFIG_SILENT_CONSOLE

command, neither one is working (the lines printed out are still the same and the boot time didn't change). Does somebody see the error ?

score 3 · Answer 1 · answered Mar 03 '14 at 22:36

3

For my target, U-Boot baseline 2013.10, silent environment variable works at kernel boot time, but it needed more defines:

#define CONFIG_SILENT_CONSOLE 
#define CONFIG_SYS_DEVICE_NULLDEV
#define CONFIG_SILENT_CONSOLE_UPDATE_ON_SET

That also killed kernel serial console after successful boot, until I added

#define CONFIG_SILENT_U_BOOT_ONLY

Refer to README.silent for more info.

answered Mar 03 '14 at 22:36

Joe Kul

2,454
16
16

unfortunately that didn't change a thing. Can you please tell me on which position you put them in your board-header file ? Maybe it's because of this. Thanks – user3085931 Mar 04 '14 at 08:10
1

Those lines went in before #include "config_cmd_default.h". But I don't think their position will matter. For your debug, you may try doing "setenv silent 1" at command line. That should lock the console until reboot, it may tell what is / is not working for you. Also note you can do "setenv bootcmd 'setenv silent 1;bootm'" (then "run bootcmd") at command line, in place of CONFIG_BOOTCOMMAND+rebuild. I trust you are seeing build time stamp change on each u-boot rebuild? – Joe Kul Mar 04 '14 at 16:45
Hmmm... yes as mentioned in the top-post I've already applied the bootcommands. And I checked them by entering U-Boot during boot and viewing the environmental variables with "printenv". So these commands like setenv silent 1 was already here. BTW: the command "setenv verify n", which i put into the bootcommands is working. – user3085931 Mar 05 '14 at 07:36
1

I found that having "silent=1" already set in persistent storage had no effect on the next reboot. Doing "setenv silent; setenv silent 1" did have effect. This seems like the purpose of CONFIG_SILENT_CONSOLE_UPDATE_ON_SET. I think you would find it useful to experiment by setting environment variables at the command line. – Joe Kul Mar 05 '14 at 17:10
You were talking about rebooting, actually I want to generate Images where the device with the given settings already have an effect on the very first boot (like the setenv verify n did) – user3085931 Mar 06 '14 at 08:30

score 0 · Accepted Answer · edited Jul 10 '21 at 03:42

0

U-Boot is doing exactly what it should (silencing the output) with the following command:

#define CONFIG_EXTRA_ENV_SETTINGS \

        "silent=1\0" \

Why doesn't U-Boot disable the console output

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