wpi doesn't work again

Hi,

Now I have current installed on my machine. I built the world about a
month ago and the wpi driver works well.
But now it doesn't work again. All the configuration files remains
untouched since last built. Here is the information.
Then I boot the kernel.old/kernel, which is the backup Current kernel
built month ago, every thing works fine.

localhost# tail KERNEL
device pci
options VESA
options SC_PIXEL_MODE
device sound
device snd_hda
device wpi
device wpifw
device wlan
device wlan_amrr
device firmware

localhost# cat /boot/loader.conf
legal.intel_wpi.license_ack=1

localhost# dmesg|grep wpi
wpi0: <Intel(R) Pro/Wireless 3945ABC> mem 0xefcff000-0xefcfffff irq 16
at device 0.0 on pci 11
wpi0:[ITHREAD]

localhost# ifconfig wpi0 up scan
ifconfig:unable to get scan results

localhost# dmesg|grep wpi
wpi0: <Intel(R) Pro/Wireless 3945ABC> mem 0xefcff000-0xefcfffff irq 16
at device 0.0 on pci 11
wpi0:[ITHREAD]
wpi0: timeout resetting Tx ring 1
wpi0: timeout resetting Tx ring 3
wpi0: timeout resetting Tx ring 4

if I turn the radio down and up again, then
localhost# ifconfig wpi0 down
localhost# ifconfig wpi0 up scan
ifconfig:unable to get scan results

the dmesg message also have the following information:
wpi0: could not lock memory.


I hope this information helpful. and I hope this problem can be fixed soom.

Yue Wang