doc/README.silent

   1 The config option CONFIG_SILENT_CONSOLE can be used to quiet messages
   2 on the console.  If the option has been enabled, the output can be
   3 silenced by setting the environment variable "silent".  The variable
   4 is latched into the global data at an early stage in the boot process
   5 so deleting it with "setenv" will not take effect until the system is
   6 restarted.
   7
   8 The following actions are taken if "silent" is set at boot time:
   9
  10  - Until the console devices have been initialized, output has to be
  11    suppressed by testing for the flag "GD_FLG_SILENT" in "gd->flags".
  12
  13  - When the console devices have been initialized, "stdout" and
  14    "stderr" are set to "nulldev", so subsequent messages are
  15    suppressed automatically. Make sure to enable "nulldev" by
  16    #defining CONFIG_SYS_DEVICE_NULLDEV in your board config file.
  17
  18  - When booting a linux kernel, the "bootargs" are fixed up so that
  19    the argument "console=" will be in the command line, no matter how
  20    it was set in "bootargs" before.