diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt
index ff16df2..d960dc0 100644
--- a/docs/qapi-code-gen.txt
+++ b/docs/qapi-code-gen.txt
@@ -236,6 +236,7 @@
 === Enumeration types ===
 
 Usage: { 'enum': STRING, 'data': ARRAY-OF-STRING }
+       { 'enum': STRING, '*prefix': STRING, 'data': ARRAY-OF-STRING }
 
 An enumeration type is a dictionary containing a single 'data' key
 whose value is a list of strings.  An example enumeration is:
@@ -247,6 +248,13 @@
 represents multiple words, use '-' between words.  The string 'max' is
 not allowed as an enum value, and values should not be repeated.
 
+The enum constants will be named by using a heuristic to turn the
+type name into a set of underscore separated words. For the example
+above, 'MyEnum' will turn into 'MY_ENUM' giving a constant name
+of 'MY_ENUM_VALUE1' for the first value. If the default heuristic
+does not result in a desirable name, the optional 'prefix' field
+can be used when defining the enum.
+
 The enumeration values are passed as strings over the Client JSON
 Protocol, but are encoded as C enum integral values in generated code.
 While the C code starts numbering at 0, it is better to use explicit
diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py
index f2428f3..a8453d1 100644
--- a/scripts/qapi-types.py
+++ b/scripts/qapi-types.py
@@ -101,20 +101,20 @@
 
     return ret
 
-def generate_enum_lookup(name, values):
+def generate_enum_lookup(name, values, prefix=None):
     ret = mcgen('''
 
 const char *const %(name)s_lookup[] = {
 ''',
                 name=c_name(name))
     for value in values:
-        index = c_enum_const(name, value)
+        index = c_enum_const(name, value, prefix)
         ret += mcgen('''
     [%(index)s] = "%(value)s",
 ''',
                      index = index, value = value)
 
-    max_index = c_enum_const(name, 'MAX')
+    max_index = c_enum_const(name, 'MAX', prefix)
     ret += mcgen('''
     [%(max_index)s] = NULL,
 };
@@ -122,7 +122,7 @@
         max_index=max_index)
     return ret
 
-def generate_enum(name, values):
+def generate_enum(name, values, prefix=None):
     name = c_name(name)
     lookup_decl = mcgen('''
 
@@ -141,7 +141,7 @@
 
     i = 0
     for value in enum_values:
-        enum_full_value = c_enum_const(name, value)
+        enum_full_value = c_enum_const(name, value, prefix)
         enum_decl += mcgen('''
     %(enum_full_value)s = %(i)d,
 ''',
@@ -348,9 +348,11 @@
     if expr.has_key('struct'):
         ret += generate_fwd_struct(expr['struct'])
     elif expr.has_key('enum'):
-        ret += generate_enum(expr['enum'], expr['data'])
+        ret += generate_enum(expr['enum'], expr['data'],
+                             expr.get('prefix'))
         ret += generate_fwd_enum_struct(expr['enum'])
-        fdef.write(generate_enum_lookup(expr['enum'], expr['data']))
+        fdef.write(generate_enum_lookup(expr['enum'], expr['data'],
+                                        expr.get('prefix')))
     elif expr.has_key('union'):
         ret += generate_fwd_struct(expr['union'])
         enum_define = discriminator_find_enum_define(expr)
diff --git a/scripts/qapi.py b/scripts/qapi.py
index 88fa073..c4423b7 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -634,11 +634,15 @@
 def check_enum(expr, expr_info):
     name = expr['enum']
     members = expr.get('data')
+    prefix = expr.get('prefix')
     values = { 'MAX': '(automatic)' }
 
     if not isinstance(members, list):
         raise QAPIExprError(expr_info,
                             "Enum '%s' requires an array for 'data'" % name)
+    if prefix is not None and not isinstance(prefix, str):
+        raise QAPIExprError(expr_info,
+                            "Enum '%s' requires a string for 'prefix'" % name)
     for member in members:
         check_name(expr_info, "Member of enum '%s'" %name, member,
                    enum_member=True)
@@ -693,7 +697,7 @@
         expr = expr_elem['expr']
         info = expr_elem['info']
         if expr.has_key('enum'):
-            check_keys(expr_elem, 'enum', ['data'])
+            check_keys(expr_elem, 'enum', ['data'], ['prefix'])
             add_enum(expr['enum'], info, expr['data'])
         elif expr.has_key('union'):
             check_keys(expr_elem, 'union', ['data'],
@@ -813,7 +817,9 @@
         new_name += c
     return new_name.lstrip('_').upper()
 
-def c_enum_const(type_name, const_name):
+def c_enum_const(type_name, const_name, prefix=None):
+    if prefix is not None:
+        type_name = prefix
     return camel_to_upper(type_name + '_' + const_name)
 
 c_name_trans = string.maketrans('.-', '__')
diff --git a/tests/Makefile b/tests/Makefile
index 34c6136..1951b1d 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -221,7 +221,8 @@
 	comments.json empty.json enum-empty.json enum-missing-data.json \
 	enum-wrong-data.json enum-int-member.json enum-dict-member.json \
 	enum-clash-member.json enum-max-member.json enum-union-clash.json \
-	enum-bad-name.json funny-char.json indented-expr.json \
+	enum-bad-name.json enum-bad-prefix.json \
+	funny-char.json indented-expr.json \
 	missing-type.json bad-ident.json ident-with-escape.json \
 	escape-outside-string.json unknown-escape.json \
 	escape-too-short.json escape-too-big.json unicode-str.json \
diff --git a/tests/qapi-schema/enum-bad-prefix.err b/tests/qapi-schema/enum-bad-prefix.err
new file mode 100644
index 0000000..399f5f7
--- /dev/null
+++ b/tests/qapi-schema/enum-bad-prefix.err
@@ -0,0 +1 @@
+tests/qapi-schema/enum-bad-prefix.json:2: Enum 'MyEnum' requires a string for 'prefix'
diff --git a/tests/qapi-schema/enum-bad-prefix.exit b/tests/qapi-schema/enum-bad-prefix.exit
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/tests/qapi-schema/enum-bad-prefix.exit
@@ -0,0 +1 @@
+1
diff --git a/tests/qapi-schema/enum-bad-prefix.json b/tests/qapi-schema/enum-bad-prefix.json
new file mode 100644
index 0000000..996f628
--- /dev/null
+++ b/tests/qapi-schema/enum-bad-prefix.json
@@ -0,0 +1,2 @@
+# The prefix must be a string type
+{ 'enum': 'MyEnum', 'data': [ 'one' ], 'prefix': [ 'fish' ] }
diff --git a/tests/qapi-schema/enum-bad-prefix.out b/tests/qapi-schema/enum-bad-prefix.out
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tests/qapi-schema/enum-bad-prefix.out
diff --git a/tests/qapi-schema/qapi-schema-test.json b/tests/qapi-schema/qapi-schema-test.json
index a9e5aab..677190c 100644
--- a/tests/qapi-schema/qapi-schema-test.json
+++ b/tests/qapi-schema/qapi-schema-test.json
@@ -6,6 +6,11 @@
 { 'struct': 'NestedEnumsOne',
   'data': { 'enum1': 'EnumOne', '*enum2': 'EnumOne', 'enum3': 'EnumOne', '*enum4': 'EnumOne' } }
 
+# for testing override of default naming heuristic
+{ 'enum': 'QEnumTwo',
+  'prefix': 'QENUM_TWO',
+  'data': [ 'value1', 'value2' ] }
+
 # for testing nested structs
 { 'struct': 'UserDefOne',
   'base': 'UserDefZero',        # intentional forward reference
diff --git a/tests/qapi-schema/qapi-schema-test.out b/tests/qapi-schema/qapi-schema-test.out
index b0b7187..32f17c5 100644
--- a/tests/qapi-schema/qapi-schema-test.out
+++ b/tests/qapi-schema/qapi-schema-test.out
@@ -1,5 +1,6 @@
 [OrderedDict([('enum', 'EnumOne'), ('data', ['value1', 'value2', 'value3'])]),
  OrderedDict([('struct', 'NestedEnumsOne'), ('data', OrderedDict([('enum1', 'EnumOne'), ('*enum2', 'EnumOne'), ('enum3', 'EnumOne'), ('*enum4', 'EnumOne')]))]),
+ OrderedDict([('enum', 'QEnumTwo'), ('prefix', 'QENUM_TWO'), ('data', ['value1', 'value2'])]),
  OrderedDict([('struct', 'UserDefOne'), ('base', 'UserDefZero'), ('data', OrderedDict([('string', 'str'), ('*enum1', 'EnumOne')]))]),
  OrderedDict([('struct', 'UserDefZero'), ('data', OrderedDict([('integer', 'int')]))]),
  OrderedDict([('struct', 'UserDefTwoDictDict'), ('data', OrderedDict([('userdef', 'UserDefOne'), ('string', 'str')]))]),
@@ -33,6 +34,7 @@
  OrderedDict([('event', '__ORG.QEMU_X-EVENT'), ('data', '__org.qemu_x-Struct')]),
  OrderedDict([('command', '__org.qemu_x-command'), ('data', OrderedDict([('a', ['__org.qemu_x-Enum']), ('b', ['__org.qemu_x-Struct']), ('c', '__org.qemu_x-Union2'), ('d', '__org.qemu_x-Alt')])), ('returns', '__org.qemu_x-Union1')])]
 [{'enum_name': 'EnumOne', 'enum_values': ['value1', 'value2', 'value3']},
+ {'enum_name': 'QEnumTwo', 'enum_values': ['value1', 'value2']},
  {'enum_name': '__org.qemu_x-Enum', 'enum_values': ['__org.qemu_x-value']},
  {'enum_name': 'UserDefAlternateKind', 'enum_values': None},
  {'enum_name': 'UserDefNativeListUnionKind', 'enum_values': None},