Disable serial console ttymxc0

[Lam Eddie]

Dear Sir,

I would like to use the serial port ttymxc0 for my Python application.

Therefore, I want to disable the serial console from ttymxc0 on wandboard with Ubuntu 12.04.

In order to do this, I did two things:

(1)

I modified(comment) the /etc/init/auto-serial-console.conf as follows:

#respawn

#exec /bin/auto-serial-console

(2)

I modified(delete the wording) from the /boot/linux.config as follows:

delete the wording "console=ttymxc0,115200" from the line below.

CONFIG_CMDLINE="noinitrd root=/dev/mtdblock2 rw rootfstype=jffs2 ip=off"

Then, I re-boot the wandboard, but the serial console cannot be disabled. 

Please advice.

Thanks.

Eddie

[nizamov...@gmail.com]

Hi,

1) cat /proc/cmdline to check the actual cmdline for the kernel
2) where you changed it? I can not check it right now but /boot/linux.config seems the wrong place for me. I guess it should be somewhere in /boot/uboot/uEnv.txt

Regards,

[Lam Eddie]

Dear nizamov.shawkat

1. After cat /proc/cmdline, I saw the "console=ttymxc0....." still in the cmdline. 

2. I captured the screen of /etc/boot and show the linux.config inside. Please help.

Thanks.

Regards,

Eddie

[nizamov...@gmail.com]

I see, linux.config is just the build config of the kernel. As far as I understand, then you have also to change the CONFIG_CMDLINE_FROM_BOOTLOADER to no, and then rebuild the kernel to make kernel use this cmdline. I guess that this is the config of the stock kernel and you do not want to mess with kernel compilation.

The other, easier, way is to set the file /boot/uEnv.txt.  You have to set mmcargs in it to the correct line - that means the line, which you have now, minus console config. I am not very good at this, you have to look out for the example uenv.txt and modify it. 

Or you might want to disable the console after boot - then look in the /etc - there should be some file with getty and ttymxc, most probably /etc/init/serial.conf (can not check it right now).

Best regards,