I tried your patch, and configured in the ec device. It didn't crash 
anything :) However, it's spitting EC GPE errors every 20 seconds or so:

04:20:41 rex /netbsd: acpiec0: EcRequest: unable to clear EC GPE
04:20:41 rex /netbsd: acpiec0: EcRequest: unable to reenable EC GPE
04:20:41 rex /netbsd: acpiec0: EcRequest: unable to clear EC GPE
04:20:41 rex /netbsd: acpiec0: EcRequest: unable to reenable EC GPE

The machine is a Sony Vaio PCG-GRX560 laptop. There are a fair number of 
things about it that don't work right, so the EC errors might not be a 
code problem. [reboot(8) hangs, poweroff(8) [APM or APCI] puts the power 
subsystem into a wierd state where I have to remove AC and battery to 
power back on, APM doesn't return much, and the video BIOS doesn't have 
the proper table to describe the LCD screen.]

rex /netbsd: NetBSD 1.6T (REX.10 2003-05-19) #1: Mon 04:18:21 PDT 2003
rex /netbsd:    bsdsrc@rex:/usr/src/sys/arch/i386/compile/REX
rex /netbsd: total memory = 255 MB
rex /netbsd: avail memory = 232 MB
rex /netbsd: using 3290 buffers containing 13160 KB of memory
rex /netbsd: BIOS32 rev. 0 found at 0xfd890
rex /netbsd: PCI BIOS rev. 2.1 found at 0xfd9ca

rex /netbsd: acpi0 at mainbus0
rex /netbsd: acpi0: X/RSDT: OemId <  SONY,      B0,20020401>, AslId <PTL 
,00000000>
rex /netbsd: acpi0: SCI interrupting at int 9
rex /netbsd: ACPI Object Type 'Processor' (0x0c) at acpi0 not configured
rex /netbsd: acpilid0 at acpi0 (PNP0C0D): ACPI Lid Switch
rex /netbsd: acpibut0 at acpi0 (PNP0C0C): ACPI Power Button
rex /netbsd: PNP0A03 [PCI Bus] at acpi0 not configured
rex /netbsd: PNP0C02 [Plug and Play motherboard register resources] at 
acpi0 not configured
rex /netbsd: PNP0200 [AT DMA Controller] at acpi0 not configured
rex /netbsd: npx0 at acpi0 (PNP0C04)
rex /netbsd: npx0: io 0xf0-0xff irq 13
rex /netbsd: npx0: using exception 16
rex /netbsd: PNP0000 [AT Interrupt Controller] at acpi0 not configured
rex /netbsd: PNP0B00 [AT Real-Time Clock] at acpi0 not configured
rex /netbsd: PNP0800 [AT-style speaker sound] at acpi0 not configured
rex /netbsd: PNP0100 [AT Timer] at acpi0 not configured
rex /netbsd: PNP0303 [IBM Enhanced (101/102-key, PS/2 mouse support)] at 
acpi0 not configured
rex /netbsd: SNY9003 at acpi0 not configured
rex /netbsd: acpiec0 at acpi0 (PNP0C09): ACPI Embedded Controller
rex /netbsd: acpiec0: io 0x62,0x66
rex /netbsd: acpibat0 at acpi0 (PNP0C0A-1): ACPI Battery (Control Method)
rex /netbsd: acpibat1 at acpi0 (PNP0C0A-2): ACPI Battery (Control Method)
rex /netbsd: acpiacad0 at acpi0 (ACPI0003): ACPI AC Adapter
rex /netbsd: com0 at acpi0 (PNP0501)
rex /netbsd: com0: io 0x3f8-0x3ff irq 4
rex /netbsd: com0: ns16550a, working fifo
rex /netbsd: lpt0 at acpi0 (PNP0401)
rex /netbsd: lpt0: io 0x378-0x37f,0x778-0x77f irq 7 drq 3
rex /netbsd: SNY5001 at acpi0 not configured
rex /netbsd: PNP0C0F [PCI interrupt link device] at acpi0 not configured
rex last message repeated 7 times
rex /netbsd: acpitz0 at acpi0 (): ACPI Thermal Zone

--
Michael South
msouth@msouth.org