Early printk via EHCI debug port

modulename: ehci-dbgp.ko

configname: CONFIG_EARLY_PRINTK_DBGP

Linux Kernel Configuration
└─>Kernel hacking
└─>Early printk via EHCI debug port
In linux kernel since version 2.6.28 (release Date: 2008-12-24)  
Write kernel log output directly into the EHCI debug port.

This is useful for kernel debugging when your machine crashes very
early before the console code is initialized. For normal operation
it is not recommended because it looks ugly and doesn't cooperate
with klogd/syslogd or the X server. You should normally N here,
unless you want to debug such a crash. You need usb debug device.

source code: