diff --git a/src/calibre/gui2/viewer/control_sleep.py b/src/calibre/gui2/viewer/control_sleep.py
new file mode 100644
index 0000000000..d189cd4b27
--- /dev/null
+++ b/src/calibre/gui2/viewer/control_sleep.py
@@ -0,0 +1,39 @@
+#!/usr/bin/env python
+# vim:fileencoding=utf-8
+# License: GPL v3 Copyright: 2021, Kovid Goyal <kovid at kovidgoyal.net>
+
+
+from calibre.constants import ismacos, iswindows
+
+if iswindows:
+    from winutil import (
+        ES_CONTINUOUS, ES_DISPLAY_REQUIRED, ES_SYSTEM_REQUIRED,
+        set_thread_execution_state
+    )
+
+    def prevent_sleep(reason=''):
+        set_thread_execution_state(ES_CONTINUOUS | ES_DISPLAY_REQUIRED | ES_SYSTEM_REQUIRED)
+        print(11111111111)
+        return 1
+
+    def allow_sleep(cookie):
+        set_thread_execution_state(ES_CONTINUOUS)
+        print(2222222222)
+elif ismacos:
+    from cocoa import (
+        create_io_pm_assertion, kIOPMAssertionTypeNoDisplaySleep,
+        release_io_pm_assertion
+    )
+
+    def prevent_sleep(reason=''):
+        return create_io_pm_assertion(kIOPMAssertionTypeNoDisplaySleep, reason or 'E-book viewer automated reading in progress')
+
+    def allow_sleep(cookie):
+        release_io_pm_assertion(cookie)
+
+else:
+    def prevent_sleep(reason=''):
+        return 0
+
+    def allow_sleep(cookie):
+        pass
diff --git a/src/calibre/utils/windows/winutil.cpp b/src/calibre/utils/windows/winutil.cpp
index c20733e603..a32d610f9a 100644
--- a/src/calibre/utils/windows/winutil.cpp
+++ b/src/calibre/utils/windows/winutil.cpp
@@ -988,7 +988,7 @@ wait_named_pipe(PyObject *self, PyObject *args) {
 static PyObject*
 set_thread_execution_state(PyObject *self, PyObject *args) {
     unsigned long new_state;
-    if (!PyArg_ParseTuple(args, "k", new_state)) return NULL;
+    if (!PyArg_ParseTuple(args, "k", &new_state)) return NULL;
     if (SetThreadExecutionState(new_state) == NULL) return PyErr_SetFromWindowsErr(0);
     Py_RETURN_NONE;
 }