Some people have reported that apmd -A makes their machines hang.
Could those people try the diff below and see whether it helps?
Index: acpicpu.c
===================================================================
RCS file: /home/cvs/src/sys/dev/acpi/acpicpu.c,v
retrieving revision 1.60
diff -u -p -r1.60 acpicpu.c
--- acpicpu.c 12 Jul 2014 18:48:17 -0000 1.60
+++ acpicpu.c 13 Jul 2014 14:00:03 -0000
@@ -202,9 +202,7 @@ acpicpu_set_pdc(struct acpicpu_softc *sc
static uint8_t cpu_oscuuid[16] = { 0x16, 0xA6, 0x77, 0x40, 0x0C, 0x29,
0xBE, 0x47, 0x9E, 0xBD, 0xD8, 0x70,
0x58, 0x71, 0x39, 0x53 };
- cap = ACPI_PDC_C_C1_HALT | ACPI_PDC_P_FFH | ACPI_PDC_C_C1_FFH
- | ACPI_PDC_C_C2C3_FFH | ACPI_PDC_SMP_P_SWCOORD | ACPI_PDC_SMP_C2C3
- | ACPI_PDC_SMP_C1PT;
+ cap = ACPI_PDC_P_FFH | ACPI_PDC_C_C1_FFH;
if (aml_searchname(sc->sc_devnode, "_OSC")) {
/* Query _OSC */
