diff --git a/man/cryptsetup.8 b/man/cryptsetup.8
index b8e306a3..15fe1dd7 100644
--- a/man/cryptsetup.8
+++ b/man/cryptsetup.8
@@ -458,11 +458,18 @@ Opens the TCRYPT (a TrueCrypt-compatible) <device> and sets up
 a mapping <name>.
 
 \fB<options>\fR can be [\-\-key\-file, \-\-tcrypt\-hidden, 
-\-\-tcrypt\-system, \-\-tcrypt\-backup, \-\-readonly, \-\-test\-passphrase].
+\-\-tcrypt\-system, \-\-tcrypt\-backup, \-\-readonly, \-\-test\-passphrase,
+\-\-allow-discards].
 
 The keyfile parameter allows combination of file content with the
 passphrase and can be repeated. Note that using keyfiles is compatible
 with TCRYPT and is different from LUKS keyfile logic.
+
+\fBWARNING:\fR Option \fB\-\-allow\-discards\fR cannot be combined with
+option \fB\-\-tcrypt\-hidden\fR. For normal mapping it can cause
+\fBdestruction of hidden volume\fR (hidden volume appears as unused space
+for outer volume so this space can be discarded).
+
 .PP
 \fItcryptDump\fR <device>
 .IP
diff --git a/src/cryptsetup.c b/src/cryptsetup.c
index abdd117d..4ef34cb5 100644
--- a/src/cryptsetup.c
+++ b/src/cryptsetup.c
@@ -251,6 +251,9 @@ static int action_open_tcrypt(void)
 	if (opt_readonly)
 		flags |= CRYPT_ACTIVATE_READONLY;
 
+	if (opt_allow_discards)
+		flags |= CRYPT_ACTIVATE_ALLOW_DISCARDS;
+
 	if (activated_name)
 		r = crypt_activate_by_volume_key(cd, activated_name, NULL, 0, flags);
 out:
@@ -1628,6 +1631,11 @@ int main(int argc, const char **argv)
 		_("Option --tcrypt-hidden, --tcrypt-system or --tcrypt-backup is supported only for TCRYPT device.\n"),
 		poptGetInvocationName(popt_context));
 
+	if (opt_tcrypt_hidden && opt_allow_discards)
+		usage(popt_context, EXIT_FAILURE,
+		_("Option --tcrypt-hidden cannot be combined with --allow-discards.\n"),
+		poptGetInvocationName(popt_context));
+
 	if (opt_debug) {
 		opt_verbose = 1;
 		crypt_set_debug_level(-1);