[PATCH 1/1] Documentation: kbuild: explicitly document missing prompt

[Stephen Brennan <stephen.s.brennan@oracle.com>]

There are a few lines in the kbuild-language.rst document which
obliquely reference the behavior of config options without prompts.
But there is nothing in the obvious location that explicitly calls
out that users cannot edit config options unless they have a prompt.

Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
---
 Documentation/kbuild/kconfig-language.rst | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/kbuild/kconfig-language.rst b/Documentation/kbuild/kconfig-language.rst
index 1fb3f5e6193c3..8e9306b599cd3 100644
--- a/Documentation/kbuild/kconfig-language.rst
+++ b/Documentation/kbuild/kconfig-language.rst
@@ -54,40 +54,43 @@ applicable everywhere (see syntax).
 
 - type definition: "bool"/"tristate"/"string"/"hex"/"int"
 
   Every config option must have a type. There are only two basic types:
   tristate and string; the other types are based on these two. The type
   definition optionally accepts an input prompt, so these two examples
   are equivalent::
 
 	bool "Networking support"
 
   and::
 
 	bool
 	prompt "Networking support"
 
 - input prompt: "prompt" <prompt> ["if" <expr>]
 
   Every menu entry can have at most one prompt, which is used to display
   to the user. Optionally dependencies only for this prompt can be added
   with "if".
+  If a prompt is not set, then the config option cannot be changed by the user.
+  It will not appear in any menu, and even edits to ``.config`` cannot alter it.
+  It can still be set via "default" and "select" (see below).
 
 - default value: "default" <expr> ["if" <expr>]
 
   A config option can have any number of default values. If multiple
   default values are visible, only the first defined one is active.
   Default values are not limited to the menu entry where they are
   defined. This means the default can be defined somewhere else or be
   overridden by an earlier definition.
   The default value is only assigned to the config symbol if no other
   value was set by the user (via the input prompt above). If an input
   prompt is visible the default value is presented to the user and can
   be overridden by him.
   Optionally, dependencies only for this default value can be added with
   "if".
 
  The default value deliberately defaults to 'n' in order to avoid bloating the
  build. With few exceptions, new config options should not change this. The
  intent is for "make oldconfig" to add as little as possible to the config from
  release to release.
 
-- 
2.43.5