diff --git a/src/target/cortex_m.c b/src/target/cortex_m.c
index 08b3661ea..0c1a99fc0 100644
--- a/src/target/cortex_m.c
+++ b/src/target/cortex_m.c
@@ -656,13 +656,9 @@ static int cortex_m_poll(struct target *target)
 		}
 	}
 
-	/* REVISIT when S_SLEEP is set, it's in a Sleep or DeepSleep state.
-	 * How best to model low power modes?
-	 */
-
 	if (target->state == TARGET_UNKNOWN) {
-		/* check if processor is retiring instructions */
-		if (cortex_m->dcb_dhcsr & S_RETIRE_ST) {
+		/* check if processor is retiring instructions or sleeping */
+		if (cortex_m->dcb_dhcsr & S_RETIRE_ST || cortex_m->dcb_dhcsr & S_SLEEP) {
 			target->state = TARGET_RUNNING;
 			retval = ERROR_OK;
 		}
diff --git a/src/target/target.h b/src/target/target.h
index 44463b74f..b9ae2f78e 100644
--- a/src/target/target.h
+++ b/src/target/target.h
@@ -47,7 +47,7 @@ struct gdb_fileio_info;
 
 /*
  * TARGET_UNKNOWN = 0: we don't know anything about the target yet
- * TARGET_RUNNING = 1: the target is executing user code
+ * TARGET_RUNNING = 1: the target is executing or ready to execute user code
  * TARGET_HALTED  = 2: the target is not executing code, and ready to talk to the
  * debugger. on an xscale it means that the debug handler is executing
  * TARGET_RESET   = 3: the target is being held in reset (only a temporary state,