kernel code reading: pci dma ops setup on power
kernel code reading: hotplug in kernel

This directory will focus on the hotplug infrastructure in kernel.

After investigation, there are several related parts to do the hotplug.
1. uevent
2. udev
3. udevadm

This directory will expand the knowledge in those areas.
kernel code test: call_usermodehelper

Function call_usermodehelper() could be used in kernel space to invoke a
userspace application.

Very interesting.