isdn/gigaset: improve error handling querying firmware version

commit e055d03d upstream.

An out-of-place "OK" response to the "AT+GMR" (get firmware version)
command turns out to be, more often than not, a delayed response to
a previous command rather than an actual error, so continue waiting
for the version number in that case.
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/isdn/gigaset/ev-layer.c

@@ -190,6 +190,7 @@ struct reply_t gigaset_tab_nocid[] =
 								  ACT_INIT} },
 	{RSP_OK,	121, 121, -1,			  0,  0, {ACT_GOTVER,
 								  ACT_INIT} },
+	{RSP_NONE,	121, 121, -1,			120,  0, {ACT_GETSTRING} },
 
 /* leave dle mode */
 	{RSP_INIT,	  0,   0, SEQ_DLE0,		201,  5, {0},	"^SDLE=0\r"},
@@ -1314,8 +1315,9 @@ static void do_action(int action, struct cardstate *cs,
 		s = ev->ptr;
 
 		if (!strcmp(s, "OK")) {
+			/* OK without version string: assume old response */
 			*p_genresp = 1;
-			*p_resp_code = RSP_ERROR;
+			*p_resp_code = RSP_NONE;
 			break;
 		}