diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 6f479bd..9ecb64e 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -4621,7 +4621,7 @@
 	in Insert mode as specified with the 'indentkeys' option.
 	When this option is not empty, it overrules the 'cindent' and
 	'smartindent' indenting.  When 'lisp' is set, this option is
-	overridden by the Lisp indentation algorithm.
+	is only used when 'lispoptions' contains "expr:1".
 	When 'paste' is set this option is not used for indenting.
 	The expression is evaluated with |v:lnum| set to the line number for
 	which the indent is to be computed.  The cursor is also in this line
@@ -5063,6 +5063,17 @@
 	calling an external program if 'equalprg' is empty.
 	This option is not used when 'paste' is set.
 
+						*'lispoptions'* *'lop'*
+'lispoptions' 'lop'	string	(default "")
+			local to buffer
+	Comma-separated list of items that influence the Lisp indenting when
+	enabled with the |'lisp'| option.  Currently only one item is
+	supported:
+		expr:1	use 'indentexpr' for Lisp indenting when it is set
+		expr:0	do not use 'indentexpr' for Lisp indenting (default)
+	Note that when using 'indentexpr' the `=` operator indents all the
+	lines, otherwise the first line is not indented (Vi-compatible).
+
 						*'lispwords'* *'lw'*
 'lispwords' 'lw'	string	(default is very long)
 			global or local to buffer |global-local|