I am trying to upgrade my kernel from 2.6.18-274 to 2.6.39 for some wireless card drivers.

When I boot into the new kernel I get the "Can't find root filesystem / error mounting /dev/root" googling led me to this page http://fedoraproject.org/wiki/Common_kernel_problems#Can.27t_find_root_filesystem_.2F_error_mounting_.2Fdev.2Froot

From what I am reading seems to be an issue with a driver for my SATA controller or HD, but I can't find what option I need to add to the kernel. Doing a diff from the old initrd to the new one gives me the following:

root-> diff /tmp/kafter /tmp/kbefore 
6a7,8
> lib/dm-message.ko
> lib/dm-region_hash.ko
8a11
> lib/dm-raid45.ko
13d15
< lib/dm-region-hash.ko
16a19
> lib/dm-mem-cache.ko

Do I need any of those? not sure if I would need dm-raid45.ko as I am not running a raid. I have the same SATA and IDE options configured for both kernels so not sure what else to look for, any help is appreciated.

Additionally here is the HW info:

00:1f.2 IDE interface: Intel Corporation 82801FB/FW (ICH6/ICH6W) SATA Controller (rev 03) (prog-if 8f [Master SecP SecO PriP PriO])
    Subsystem: Hewlett-Packard Company Unknown device 3006
    Flags: bus master, 66MHz, medium devsel, latency 0, IRQ 233
    I/O ports at 1818 [size=8]
    I/O ports at 1830 [size=4]
    I/O ports at 1820 [size=8]
    I/O ports at 1834 [size=4]
    I/O ports at 14f0 [size=16]
    Capabilities: [70] Power Management version 2

root-> smartctl -a /dev/sda
...

=== START OF INFORMATION SECTION ===
Device Model:     WDC WD5000AADS-00S9B0