[v6,6/7] udevng: Set the QMI minimum service request period for Quectel BG96 modems.

Commit Message

Grant Erickson March 19, 2025, 7:22 p.m. UTC

The Quectel Wireless Solutions Co., Ltd. (2c7c) BG96 CAT-M1/NB-IoT
modem (0296) has a firmware issue where it can lock up and hang (not
responding to subsequent commands) due to high QMI service request
arrival rates. If the vendor and model match those, then rate limit
QMI service requests to no more than one every 2,000 us.
---
 plugins/udevng.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

Patch

diff --git a/plugins/udevng.c b/plugins/udevng.c
index 64875a47752b..b8df66de5c71 100644
--- a/plugins/udevng.c
+++ b/plugins/udevng.c
@@ -1118,6 +1118,20 @@  static gboolean setup_quectelqmi(struct modem_info *modem)
 
 	DBG("%s", modem->syspath);
 
+	/*
+	 * The Quectel Wireless Solutions Co., Ltd. (2c7c) BG96
+	 * CAT-M1/NB-IoT modem (0296) has a firmware issue where it can
+	 * lock up and hang (not responding to subsequent commands) due to
+	 * high QMI service request arrival rates. If the vendor and model
+	 * match those, then rate limit QMI service requests to no more
+	 * than one every 2,000 us.
+	 */
+	if (l_streq0(modem->vendor, "2c7c")) {
+		if (l_streq0(modem->model, "0296"))
+			ofono_modem_set_integer(modem->modem,
+				"RequestThrottleTimeUs", 2000);
+	}
+
 	for (list = modem->devices; list; list = g_slist_next(list)) {
 		const struct device_info *info = list->data;
 		const char *subsystem =