diff --git a/sys/dev/acpi_support/acpi_ibm.c b/sys/dev/acpi_support/acpi_ibm.c
--- a/sys/dev/acpi_support/acpi_ibm.c
+++ b/sys/dev/acpi_support/acpi_ibm.c
@@ -1447,8 +1447,13 @@
 
 	ACPI_SERIAL_BEGIN(ibm);
 	switch (arg) {
+	/*
+	 * XXX "Suspend-to-RAM" here is as opposed to suspend-to-disk, but it is
+	 * fine if our suspend sleep state transition request puts us in s2idle
+	 * instead of suspend-to-RAM.
+	 */
 	case IBM_EVENT_SUSPEND_TO_RAM:
-		power_pm_suspend(POWER_SLEEP_STATE_SUSPEND);
+		power_pm_suspend(POWER_SSTATE_TRANSITION_SUSPEND);
 		break;
 
 	case IBM_EVENT_BLUETOOTH:
diff --git a/sys/dev/syscons/syscons.c b/sys/dev/syscons/syscons.c
--- a/sys/dev/syscons/syscons.c
+++ b/sys/dev/syscons/syscons.c
@@ -3987,10 +3987,10 @@
 				break;
 
 			case SUSP:
-				power_pm_suspend(POWER_SLEEP_STATE_SUSPEND);
+				power_pm_suspend(POWER_SSTATE_TRANSITION_SUSPEND);
 				break;
 			case STBY:
-				power_pm_suspend(POWER_SLEEP_STATE_STANDBY);
+				power_pm_suspend(POWER_SSTATE_TRANSITION_STANDBY);
 				break;
 
 			case DBG:
diff --git a/sys/dev/vt/vt_core.c b/sys/dev/vt/vt_core.c
--- a/sys/dev/vt/vt_core.c
+++ b/sys/dev/vt/vt_core.c
@@ -804,11 +804,11 @@
 		return (1);
 	case SPCLKEY | STBY: /* XXX Not present in kbdcontrol parser. */
 		/* Put machine into Stand-By mode. */
-		power_pm_suspend(POWER_SLEEP_STATE_STANDBY);
+		power_pm_suspend(POWER_SSTATE_TRANSITION_STANDBY);
 		return (1);
 	case SPCLKEY | SUSP: /* kbdmap(5) keyword `susp`. */
 		/* Suspend machine. */
-		power_pm_suspend(POWER_SLEEP_STATE_SUSPEND);
+		power_pm_suspend(POWER_SSTATE_TRANSITION_SUSPEND);
 		return (1);
 	}
 
diff --git a/sys/kern/subr_power.c b/sys/kern/subr_power.c
--- a/sys/kern/subr_power.c
+++ b/sys/kern/subr_power.c
@@ -176,25 +176,25 @@
 }
 
 void
-power_pm_suspend(int state)
+power_pm_suspend(enum power_sstate_transition trans)
 {
 	enum power_stype	stype;
 
 	if (power_pm_fn == NULL)
 		return;
 
-	switch (state) {
-	case POWER_SLEEP_STATE_STANDBY:
+	switch (trans) {
+	case POWER_SSTATE_TRANSITION_STANDBY:
 		stype = power_standby_stype;
 		break;
-	case POWER_SLEEP_STATE_SUSPEND:
+	case POWER_SSTATE_TRANSITION_SUSPEND:
 		stype = power_suspend_stype;
 		break;
-	case POWER_SLEEP_STATE_HIBERNATE:
+	case POWER_SSTATE_TRANSITION_HIBERNATE:
 		stype = power_hibernate_stype;
 		break;
 	default:
-		printf("%s: unknown sleep state %d\n", __func__, state);
+		printf("%s: unknown sleep state %d\n", __func__, trans);
 		return;
 	}
 
diff --git a/sys/sys/power.h b/sys/sys/power.h
--- a/sys/sys/power.h
+++ b/sys/sys/power.h
@@ -45,22 +45,25 @@
 #define POWER_CMD_SUSPEND		0x00
 
 /*
- * Sleep state.
+ * Sleep state transition requests.
  *
  * These are high-level sleep states that the system can enter.  They map to
  * a specific generic sleep type (enum power_stype).
  */
-#define POWER_SLEEP_STATE_STANDBY	0x00
-#define POWER_SLEEP_STATE_SUSPEND	0x01
-#define POWER_SLEEP_STATE_HIBERNATE	0x02
+enum power_sstate_transition {
+	// TODO Is there a reason we'd want to explicitly set these values?
+	POWER_SSTATE_TRANSITION_STANDBY,
+	POWER_SSTATE_TRANSITION_SUSPEND,
+	POWER_SSTATE_TRANSITION_HIBERNATE,
+};
 
 /*
  * Sleep type.
  *
  * These are the specific generic methods of entering a sleep state.  E.g.
- * POWER_SLEEP_STATE_SUSPEND could be set to enter either suspend-to-RAM (which
- * is S3 on ACPI systems), or suspend-to-idle (S0ix on ACPI systems).  This
- * would be done through the kern.power.suspend sysctl.
+ * POWER_SSTATE_TRANSITION_SUSPEND could be set to enter either suspend-to-RAM
+ * (which is S3 on ACPI systems), or suspend-to-idle (S0ix on ACPI systems).
+ * This would be done through the kern.power.suspend sysctl.
  */
 enum power_stype {
 	POWER_STYPE_AWAKE,
@@ -94,7 +97,7 @@
 			void *_pm_arg,
 			bool _pm_supported[static POWER_STYPE_COUNT]);
 extern u_int	 power_pm_get_type(void);
-extern void	 power_pm_suspend(int);
+extern void	 power_pm_suspend(enum power_sstate_transition _trans);
 
 /*
  * System power API.