Comment 53 for bug 548513

This work for me:

The Jerone's patch was the soluction for my eSATA external hard disk.

!!!!
So changing /lib/udev/rules.d/85-hdparm.rules to:
ACTION=="add", SUBSYSTEM=="block", KERNEL=="[sh]d[a-z]", \
 ENV{ID_PATH}!="pci-*-ieee1394-*|pci-*-usb-*", \
 RUN+="/lib/udev/hdparm"
!!!

but the problem continue with my USB external disk
I have found the solution for this problem by putting the parameter acpi=off on the end of the kernel options.

/boot/grub/grub.cfg

menuentry "Ubuntu 10.04 LTS (10.04) (on /dev/sdb5)" {
 insmod ext2
 set root='(hd1,5)'
 search --no-floppy --fs-uuid --set de5a18c4-1a61-4f0b-aab0-941623a0cb01
 linux /boot/vmlinuz-2.6.32-22-generic-pae root=/dev/sdb5 ro quiet splash acpi=off
 initrd /boot/initrd.img-2.6.32-22-generic-pae
}

https://bugs.launchpad.net/ubuntu/+bug/575646/comments/6

[0:0:0:0] disk WDC WD16 00JS-22MHB0 1C03 /dev/sdc
[1:0:0:0] disk ATA WDC WD3200BEKT-6 12.0 /dev/sda
[2:0:0:0] cd/dvd hp CDDVDW TS-L633M 0301 /dev/sr0
[6:0:0:0] disk ATA ST3500320AS SD15 /dev/sdb