Terminate UART Console

• Related Documentation:
  • Serial Console
    
    
  • Cannot Disable Serial Console on AR71xx
  • Debugging Techniques
  • Monitoring Session - Using Basic Linux Utility Programs
    
    
• Forum Discussion:
  • Disable UART Console (without recompiling the patched firmware)

If needing to utilize the terminal for RAW data/Modem data, reconfigure /dev/tty via the coreutils-stty module.

1. Add kernel.printk = 0 4 1 7 to /etc/sysctl.d/:

    echo "kernel.printk = 0 4 1 7" > /etc/sysctl.d/10-printk.conf

2. Edit /etc/inittab:
   1. Comment out lines starting with ttyS0:*, ttyATH0:* and ::askconsole:*

      sed -i -r -e "s/^((ttyS0|ttyATH0|::askconsole):.*)/#\0/" /etc/inittab

3. Reboot

1. Modify Kernel config in <buildroot>/target/linux/ar71xx/config-x.xx: ^{(x.xx = kernel version)}
   1. Terminates Kernel console output early:
      1. Add CONFIG_MESSAGE_LOGLEVEL_DEFAULT=0
         
         
   2. Terminates Kernel console output later in boot process:
      1. Add loglevel=0 to CONFIG_CMDLINE=“rootfstype=squashfs,jffs2 noinitrd”

         sed -i -r -e 's/(CONFIG_CMDLINE=".*)(")/\1 loglevel=0\2/' target/linux/ar71xx/config-x.xx

2. Recompile Kernel:

   make target/linux/{clean,prepare} V=s QUILT=1 && make V=s

3. Flash recompiled image