Dell Optiplex 790 Workstations hang while rebooting with CentOS 6

I'm working on deploying a large number of Dell Optiplex 790 workstations using kickstart and CentOS 6.

During the initial testing I found that the 790's wouldn't completely reboot with CentOS 6 installed or booted into the install media. They'd get as far as "Restarting".

The solution is to pass an option to the kernel:

reboot=pci

This can be added manually to the grub configuration file for systems already installed. For kickstarting:

1. Add the option in your kickstart file

bootloader --location=mbr --driveorder=sda --append="crashkernel=auto rhgb quiet reboot=pci" --md5pass=$1$.xxxxx

2. During the initial boot off of the CD/DVD, press TAB to alter to boot options (this is all one continuous line broken into multiple for readability)

> vmlinuz initrd=initrd.img ks=http://192.168.1.5/ks/el6/wks1.cfg
    ip=192.168.1.100 netmask=255.255.255.0 gateway=192.168.1.1 nameserver=192.168.1.1
    ksdevice=eth0 reboot=pci