diff -u -r /usr/src/sys.old/dev/acpica/acpi_ec.c /usr/src/sys/dev/acpica/acpi_ec.c
--- /usr/src/sys.old/dev/acpica/acpi_ec.c	2008-05-26 23:47:22.000000000 -0500
+++ /usr/src/sys/dev/acpica/acpi_ec.c	2008-05-26 23:58:22.000000000 -0500
@@ -194,6 +194,10 @@
 TUNABLE_INT("debug.acpi.ec.timeout", &ec_timeout);
 SYSCTL_INT(_debug_acpi_ec, OID_AUTO, timeout, CTLFLAG_RW, &ec_timeout,
     EC_TIMEOUT, "Total time spent waiting for a response (poll+sleep)");
+static int	ec_extradelay = 0;
+TUNABLE_INT("debug.acpi.ec.extradelay", &ec_extradelay);
+SYSCTL_INT(_debug_acpi_ec, OID_AUTO, extradelay, CTLFLAG_RW, &ec_extradelay,
+    0, "Microseconds to delay at the start of EcWaitEvent");
 
 static ACPI_STATUS
 EcLock(struct acpi_ec_softc *sc)
@@ -812,6 +816,8 @@
 
     ACPI_SERIAL_ASSERT(ec);
     Status = AE_NO_HARDWARE_RESPONSE;
+    if (ec_extradelay > 0 && ec_extradelay < 2000)
+	AcpiOsStall(ec_extradelay);
     int need_poll = cold || rebooting || ec_polled_mode || sc->ec_suspending;
     /*
      * The main CPU should be much faster than the EC.  So the status should