earlyprintk — Show early boot messages.
Show kernel log messages that precede the initialization of
the traditional console. These messages are typically never seen
on the console unless you use this option. Enabling this can be
very useful for tracking down hardware issues. Currently, the
option can specify either the
VGA device or the serial port, but not both at the same time.
Also, only the ttyS0 or ttyS1
serial devices will work. Interaction with the standard serial
driver is not very good, and the VGA output will eventually be
overwritten by the real console.
Append ,keep in order not to disable the
messages shown by this option when the real kernel console is
initialized and takes over the system.