Disabling USB in BIOS, but still interrupts?

Disabled USB in bios altogether to try to get rid of high interrupts, making computer nearly unusable:

%CPU PID USER COMMAND
6.5 11361 root [kworker/0:0]
4.6 11479 root [kworker/1:0]
2.9 2727 fblaise /usr/lib/thunderbird-9.0/thunderbird-bin
2.2 10609 root [kworker/0:2]
1.8 2301 fblaise /usr/bin/knotify4
1.6 10025 root [kworker/1:3]
1.0 8615 root [kworker/1:1]
10.5 1373 root /usr/bin/X :0 vt7 -nr -nolisten tcp -auth /var/run/xauth/A:0-CDTMZa
0.9 9577 root [kworker/0:1]

(see http://ironman.darthgibus.net/?p=153#comments)

but procinfo still shows interrupts on usb? Is it not honoring the BIOS settings?

irq 0: 23907 timer irq 21: 0 uhci_hcd:usb4
irq 1: 171 i8042 irq 22: 2 ehci_hcd:usb1

Kernel is 3.0.0-13-generic-pae.

Any feedback welcome.

Update: From powertop:

Top causes for wakeups:
47.0% (359.8) PS/2 keyboard/mouse/touchpad interrupt
20.5% (156.8) [Rescheduling interrupts]

It’s driving me nuts… Now on opensuse 12.1 64bits.

btrfs consuming lots of sys cpu time

fblaise@snowball ~ $ ps -eo pcpu,pid,user,args | sort -k 1 -r | head -10
%CPU PID USER COMMAND
7.4 2591 root [flush-btrfs-1]
5.9 905 root [btrfs-endio-0]
4.4 2907 root [btrfs-endio-wri]
4.3 1314 root /usr/bin/X :0 vt7 -nr -nolisten tcp -auth /var/run/xauth/A:0-VjxI1a
2.7 900 root [btrfs-worker-0]
1.7 2106 fblaise /usr/bin/knotify4
1.4 2094 fblaise kwin
0.6 10 root [kworker/0:1]
0.5 3643 fblaise top

And it is only on my /home filesystem… system is currently sitting idle. Wow.

This is on a Linux Mint laptop with 3.0.0-13-generic-pae.

Anyone experienced this?