Well, I figured out that uhci_hcd was the culprit for the previous wakeups. uhci_hcd provides USB 1.1 support, which I can disable because my laptop is all USB v2. As you can see below the menu governor for 2.6.23-rc5 + hrt patch doesn’t work quite as well versus 2.6.23-rc4 + hrt patch because the CPU stays in C2 60% of time with the Wifi turned on. lspci output just for kicks.

PowerTOP 1.8 (C) 2007 Intel Corporation Collecting data for 15 seconds
Cn Avg residency
C0 (cpu running) ( 0.8%)
C1 0.0ms ( 0.0%)
C2 49.1ms (66.5%)
C3 0.7ms ( 0.0%)
C4 22.3ms (32.7%)
P-states (frequencies)
1.87 Ghz 0.0%
1.60 Ghz 0.0%
1333 Mhz 0.0%
800 Mhz 100.0%
Wakeups-from-idle per second : 28.5 interval: 15.0s
no ACPI power usage estimate available
Top causes for wakeups:
39.3% ( 10.1) <interrupt> : ipw2200, lan0
14.8% ( 3.8) <interrupt> : acpi
9.6% ( 2.5) gkrellm2 : schedule_timeout (process_timeout)
7.8% ( 2.0) xfce-mcs-manage : schedule_timeout (process_timeout)
7.0% ( 1.8) X : do_setitimer (it_real_fn)
5.5% ( 1.4) wpa_supplicant : schedule_timeout (process_timeout)
2.1% ( 0.5) wpa_cli : schedule_timeout (process_timeout)
2.1% ( 0.5) slim : do_setitimer (it_real_fn)
1.8% ( 0.5) events/0 : ipw_gather_stats (delayed_work_timer_fn)
1.6% ( 0.4) <interrupt> : ide0
1.0% ( 0.3) <kernel core> : neigh_table_init_no_netlink (neigh_periodic_timer)
0.8% ( 0.2) ifplugd : schedule_timeout (process_timeout)
0.8% ( 0.2) init : schedule_timeout (process_timeout)
0.8% ( 0.2) <kernel core> : page_writeback_init (wb_timer_fn)
0.5% ( 0.1) gaim : schedule_timeout (process_timeout)
0.5% ( 0.1) ssh-agent : schedule_timeout (process_timeout)
0.5% ( 0.1) cupsd : schedule_timeout (process_timeout)
0.3% ( 0.1) <interrupt> : PS/2 keyboard/mouse/touchpad
0.3% ( 0.1) gaim : sk_reset_timer (tcp_write_timer)
0.3% ( 0.1) <kernel core> : ipw_net_hard_start_xmit (delayed_work_timer_fn)
0.3% ( 0.1) cifsdnotifyd : schedule_timeout (process_timeout)
0.3% ( 0.1) <kernel core> : init_nonfatal_mce_checker (delayed_work_timer_fn)
0.3% ( 0.1) bash : start_this_handle (commit_timeout)
0.3% ( 0.1) xfdesktop : schedule_timeout (process_timeout)
0.3% ( 0.1) xfce4-menu-plug : schedule_timeout (process_timeout)
0.3% ( 0.1) <kernel core> : end_that_request_last (laptop_timer_fn)
0.3% ( 0.1) pdflush : schedule_timeout (process_timeout)
0.3% ( 0.1) <kernel core> : neigh_update (neigh_timer_handler)
0.3% ( 0.1) <kernel core> : init_sunrpc (delayed_work_timer_fn)
0.3% ( 0.1) cifsoplockd : schedule_timeout (process_timeout)