diff --git a/serial/serialposix.py b/serial/serialposix.py
index 913b643..30af312 100644
--- a/serial/serialposix.py
+++ b/serial/serialposix.py
@@ -730,6 +730,9 @@
         if self._inter_byte_timeout is not None:
             vmin = 1
             vtime = int(self._inter_byte_timeout * 10)
+        elif self._timeout is None:
+            vmin = 1
+            vtime = 0
         else:
             vmin = 0
             vtime = int(self._timeout * 10)
@@ -764,3 +767,6 @@
                 break
             read.extend(buf)
         return bytes(read)
+
+    # hack to make hasattr return false
+    cancel_read = property()