Panic on S3 suspend call.

Hi.

Just noted that fresh HEAD i386 system panics on suspend request when
build with INVARIANTS and WITNESS:

panic: mutex ACPI global lock owned at ../../../kern/kern_event.c:1899
cpuid = 1
KDB: enter: panic
[ thread pid 1047 tid 100138 ]
Stopped at      0x408d29df:     movl    $0,0x40dded34
db> bt
Tracing pid 1047 tid 100138 td 0x45fcb9c0
kdb_enter(40c75fe3,40c75fe3,40c74763,7c91fb1c,1,...) at 0x408d29df
panic(40c74763,40c26898,40c70d4e,76b,7c91fb40,...) at 0x4089ec96
_mtx_assert(40da08a0,0,40c70d4e,76b,7c91fb70,...) at 0x4088e227
knlist_mtx_assert_unlocked(40da08a0,4088ed2c,40da08a0,45d377c0,3,...) at
0x4086b06e
knote(45d377dc,0,0,921,0,...) at 0x4086b9ff
acpi_ReqSleepState(456c3700,3,40c2633d,c76,0,...) at 0x404e8f4b
acpiioctl(45793400,80045004,45d07810,3,45fcb9c0,...) at 0x404e9118
devfs_ioctl_f(45d820e0,80045004,45d07810,45d34a80,45fcb9c0,...) at
0x4081d1e8
kern_ioctl(45fcb9c0,3,80045004,45d07810,91fcec,...) at 0x408ebdbd
ioctl(45fcb9c0,7c91fcec,0,40cb192e,0,...) at 0x408ebf47
syscallenter(45fcb9c0,7c91fce4,40b9fa00,40dcd190,0,...) at 0x408e0b23
syscall(7c91fd28) at 0x40b9f169
Xint0x80_syscall() at 0x40b7f49a
--- syscall (54, FreeBSD ELF32, ioctl), eip = 0x28183173, esp =
0x3fbfeb1c, ebp = 0x3fbfebf8 ---
db>

-- 
Alexander Motin