I had installed FreeBSD 8.0-RC3/amd64 on a new HP dv8t Laptop and then had been upgrading system to the latest stable every couple of days.  During the process of setting the system up,  I had added the following modules to /boot/loader.conf:

zfs_load="YES"
opensolaris_load="YES"
snd_hda_load="YES"
sound_load="YES"
coretemp_load="YES"
acpi_wmi_load="YES"
acpi_hp_load="YES"
acpi_video="YES"
zlib_load="YES"
crypto_load="YES"
smbus_load="YES"
ichsmb_load="YES"
sdhci_load="YES"

When the acpi_hp kernel module was loaded, I was able to disable/enable the bluetooth device on the system using a kernel built from sources using this revision or older:

FreeBSD 8.0-STABLE #18 r199983: Fri Dec 18 02:06:33 CST 2009
Dec 18 02:18:55 dv8t01 kernel: root@dv8t01:/usr/obj/usr/src/8-stable/sys/GENERIC amd64

But when I upgraded the kernel to this revision or newer the WiFi Button fails to respond:

FreeBSD 8.0-STABLE #17 r199987: Fri Dec 18 00:38:21 CST 2009
root@dv8t01:/usr/obj/usr/src/8-stable/sys/GENERIC amd64

The only change between these two revisions is the "MFC r199016: acpi: remove 'magic' ivar" commit:

http://svn.freebsd.org/viewvc/base?view=revision&revision=199984

Another problem is that when I update to this revision or newer:

FreeBSD 8.0-STABLE #9 r200330: Thu Dec 17 10:22:04 CST 2009
Dec 17 10:37:50 dv8t01 kernel: root@dv8t01:/usr/obj/usr/src/8-stable/sys/GENERIC amd64

After the system boots and the Login prompt is displayed I get these ACPI error messages repeating every few seconds:

Dec 17 10:38:57 dv8t01 kernel: ACPI Error: No handler for Region [ERAM] (0xffffff0002a37d80) [EmbeddedControl] 20090521 evregion-430
Dec 17 10:38:57 dv8t01 kernel: ACPI Error: Region EmbeddedControl(3) has no handler 20090521 exfldio-382
Dec 17 10:38:57 dv8t01 kernel: ACPI Error (psparse-0633): Method parse/execution failed [\_TZ_.TZ01._TMP] (Node 0xffffff0002a47100), AE_NOT_EXIST
Dec 17 10:38:58 dv8t01 kernel: ACPI Error: No handler for Region [ERAM] (0xffffff0002a37d80) [EmbeddedControl] 20090521 evregion-430
Dec 17 10:38:58 dv8t01 kernel: ACPI Error: Region EmbeddedControl(3) has no handler 20090521 exfldio-382
Dec 17 10:38:58 dv8t01 kernel: ACPI Error (psparse-0633): Method parse/execution failed [\_SB_.ACAD._PSR] (Node 0xffffff0002a3e8a0), AE_NOT_EXIST
Dec 17 10:38:58 dv8t01 kernel: ACPI Error: No handler for Region [ERAM] (0xffffff0002a37d80) [EmbeddedControl] 20090521 evregion-430
Dec 17 10:38:58 dv8t01 kernel: ACPI Error: Region EmbeddedControl(3) has no handler 20090521 exfldio-382
Dec 17 10:38:58 dv8t01 kernel: ACPI Error (psparse-0633): Method parse/execution failed [\_SB_.BAT0._STA] (Node 0xffffff0002a3e700), AE_NOT_EXIST
Dec 17 10:38:58 dv8t01 kernel: ACPI Error (uteval-0329): Method execution failed [\_SB_.BAT0._STA] (Node 0xffffff0002a3e700), AE_NOT_EXIST
Dec 17 10:38:58 dv8t01 kernel: ACPI Error: No handler for Region [ERAM] (0xffffff0002a37d80) [EmbeddedControl] 20090521 evregion-430
Dec 17 10:38:58 dv8t01 kernel: ACPI Error: Region EmbeddedControl(3) has no handler 20090521 exfldio-382
Dec 17 10:38:58 dv8t01 kernel: ACPI Error (psparse-0633): Method parse/execution failed [\_SB_.BAT0._BST] (Node 0xffffff0002a3e6c0), AE_NOT_EXIST
Dec 17 10:38:58 dv8t01 kernel: ACPI Error: No handler for Region [ERAM] (0xffffff0002a37d80) [EmbeddedControl] 20090521 evregion-430
Dec 17 10:38:58 dv8t01 kernel: ACPI Error: Region EmbeddedControl(3) has no handler 20090521 exfldio-382
Dec 17 10:38:58 dv8t01 kernel: ACPI Error (psparse-0633): Method parse/execution failed [\_SB_.BAT0._STA] (Node 0xffffff0002a3e700), AE_NOT_EXIST
Dec 17 10:38:58 dv8t01 kernel: ACPI Error (uteval-0329): Method execution failed [\_SB_.BAT0._STA] (Node 0xffffff0002a3e700), AE_NOT_EXIST
Dec 17 10:38:58 dv8t01 kernel: ACPI Error: No handler for Region [ERAM] (0xffffff0002a37d80) [EmbeddedControl] 20090521 evregion-430
Dec 17 10:38:58 dv8t01 kernel: ACPI Error: Region EmbeddedControl(3) has no handler 20090521 exfldio-382
Dec 17 10:38:58 dv8t01 kernel: ACPI Error (psparse-0633): Method parse/execution failed [\_SB_.BAT0._STA] (Node 0xffffff0002a3e700), AE_NOT_EXIST
Dec 17 10:38:58 dv8t01 kernel: ACPI Error (uteval-0329): Method execution failed [\_SB_.BAT0._STA] (Node 0xffffff0002a3e700), AE_NOT_EXIST
Dec 17 10:38:58 dv8t01 kernel: ACPI Error: No handler for Region [ERAM] (0xffffff0002a37d80) [EmbeddedControl] 20090521 evregion-430
Dec 17 10:38:58 dv8t01 kernel: ACPI Error: Region EmbeddedControl(3) has no handler 20090521 exfldio-382
Dec 17 10:38:58 dv8t01 kernel: ACPI Error (psparse-0633): Method parse/execution failed [\_SB_.BAT0._BST] (Node 0xffffff0002a3e6c0), AE_NOT_EXIST

But if I back down to this revision it stops:

FreeBSD 8.0-STABLE #8 r200329: Thu Dec 17 09:43:59 CST 2009
Dec 17 10:48:32 dv8t01 kernel: root@dv8t01:/usr/obj/usr/src/8-stable/sys/GENERIC amd64

The only change between  r200329 and r200330, is "MFC r199675: Provide tunables for some of the usb sysctls that affect boot behavior."

http://svn.freebsd.org/viewvc/base?view=revision&revision=200330

This change  only adds TUNEABLE_INT's to the USB code.

I update the system to the latest revision (r200675) and it still exhibits the problem where the WiFi button is not functioning and continuous reports of ACPI Error messages after displaying the Login prompt.  I reverted the r199984 change, and now the WiFi Button can be used to disable the Bluetooth device, and there are no longer any ACPI Error messages being displayed after the system shows the Login prompt:

http://svn.freebsd.org/viewvc/base?view=revision&revision=199984

FreeBSD dv8t01 8.0-STABLE FreeBSD 8.0-STABLE #20 r200675M: Fri Dec 18 12:44:06 CST 2009
root@dv8t01:/usr/obj/usr/src/8-stable/sys/GENERIC  amd64

I have since updated to svn r200931, and when I boot an unpatched version of the kernel I get the following panic:

cpu7: <ACPI CPU> on acpi0                                                                                    
coretemp7: <CPU On-Die Thermal Sensors> on cpu7                                                              
est7: <Enhanced SpeedStep Frequency Control> on cpu7                                                         
p4tcc7: <CPU Frequency Thermal Control> on cpu7                                                              
acpi_hp0: HP event GUID detected, installing event handler                                                   
acpi_ec0: <Embedded Controller: GPE 0x666e696c, GLK, ECDT> port 0x62,0x66 on acpi0

Fata trap 12: page fault while in kernal mode
cpuid = 0; apic id = 00
fault virtual address = 0x34
fault code            = supervisor read data, page not present
instruction pointer   = 0x20:0xffffffff801cac79
stack pointer         = 0x28:0xffffffff812bfa00
frame pointer         = 0x28:0xffffffff812bfa10
code segment          = base rx0, limit 0xfffff, type 0x1b
                      = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags      = interrupt enabled, resume, IOPL = 0
current process       = 0 (swapper)
[thread pid 0 tid 100000 ]
stopped at      AcpiNsGetAttachedObject+0x9:     movq     (%rdi),%rdx
db> bt
tracing pid 0 tid 100000 0xffffffff80c282e0
AcpiNsGetAttachedObject() at AcpiNsGetAttachedObject+0x9
AcpiEvGetGpeEventInfo() at AcpiEvGetGpeEventInfo+0x75
AcpiInstallGpeHandler() at AcpiInstallGpeHandler+0x61
acpi_ec_attach() at acpi_ec_attach+0x274
device_attach() at device_attach+0x69
bus_generic_attach at bus_generic_attach+0x1a
device_attach() at device_attach+0x69
bus_generic_new_patch at bus_generic_new_patch+0xd6
bus_set_pass() at bus_set_pass+0x7a
configure() at configure+0xa
mi_start() at mi_start+0x59
btext() at btext+0x2c
db>

I reverted r199016 and the following kernel boots:

dv8t01# uname -a
FreeBSD dv8t01 8.0-STABLE FreeBSD 8.0-STABLE #1 r200931M: Thu Dec 24 00:55:43 CST 2009     root@dv8t01:/usr/obj/usr/src/8-stable/sys/GENERIC  amd64

dmesg output where unpatched kernel crashed:

cpu7: <ACPI CPU> on acpi0                                                                                    
coretemp7: <CPU On-Die Thermal Sensors> on cpu7                                                              
est7: <Enhanced SpeedStep Frequency Control> on cpu7                                                         
p4tcc7: <CPU Frequency Thermal Control> on cpu7                                                              
acpi_hp0: HP event GUID detected, installing event handler                                                   
acpi_ec0: <Embedded Controller: GPE 0x16> port 0x62,0x66 on acpi0
sc0: <System console> at flags 0x100 on isa0
sc0: VGA <16 virtual consoles, flags=0x300>

I have dumped the dsdt code from this system and when I try to compile it, I get 532 errors,  I attempted to patch the dsdt to fix some of the problems, but not sure I patched it correctly.

The files are available at:

http://www.mediafire.com/file/ztgmvi5i3r2//usr/src/asl9/swhetzel-dv8t.tgz

The swhetzel-dv8t.tgz files contains the original asl, dsl and dst files, and my attemp at patching.  As well the error messages produced when attempting to compile the dst files.

Note: I was having problems with the iasl compiler (FreeBSD 8.0) core dumping, and have installed the iasl compiler from FreeBSD 9-CURRENT.

Fix: Unknown, below is the dmesg from booting a kernel with r199016 reverted.

Patch attached with submission follows:
How-To-Repeat: Install FreeBSD Release on a HP dv8t Laptop, then upgrade the kernel to the latest stable sources (i.e r200931) and reboot.