[PATCH 05/10] gobi: ensure Set Data Format changes were applied

Some firmware accept Set Data Format command, but do not actually honor
it.  For example Quectel RM502Q happily accepts being set to 802.3
link-layer protocol, but doesn't actually change it.  Try to detect this
case and handle it appropriately.
---
 plugins/gobi.c | 35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/plugins/gobi.c b/plugins/gobi.c
index 87b54ae05f17..321a2ae0bca7 100644
--- a/plugins/gobi.c
+++ b/plugins/gobi.c
@@ -461,6 +461,33 @@ error:
 	shutdown_device(modem);
 }
 
+/*
+ * Some firmware accepts the Set Data Format command successfully, but doesn't
+ * change anything.  Try to detect and warn if that happens
+ */
+static int compare_data_format(struct gobi_data *data, struct qmi_result *result)
+{
+	struct qmi_wda_data_format expected;
+	struct qmi_wda_data_format actual;
+	int r;
+
+	if (!wda_get_data_format(data, &expected))
+		return -EPROTO;
+
+	r = qmi_wda_parse_data_format(result, &actual);
+	if (r < 0)
+		return -EBADMSG;
+
+	if (expected.ll_protocol != actual.ll_protocol ||
+			expected.ul_aggregation_protocol !=
+			actual.ul_aggregation_protocol ||
+			expected.dl_aggregation_protocol !=
+			actual.dl_aggregation_protocol)
+		return -EBADE;
+
+	return 0;
+}
+
 static void set_data_format_cb(struct qmi_result *result, void *user_data)
 {
 	struct ofono_modem *modem = user_data;
@@ -473,8 +500,12 @@ static void set_data_format_cb(struct qmi_result *result, void *user_data)
 
 	DBG("");
 
-	if (!qmi_result_set_error(result, NULL))
-		goto done;
+	if (!qmi_result_set_error(result, NULL)) {
+		if (!compare_data_format(data, result))
+			goto done;
+
+		ofono_error("Setting Data Format had no effect");
+	}
 
 	if (data->data_format == WDA_DATA_FORMAT_802_3)
 		goto error;
-- 
2.47.0