sierra: handle probing ERROR response better

The USB305 (Icera-based) apparently has a port that replies to everything
with ERROR, and that port is unusable.  Make sure it's ignored, otherwise
MM may claim it as the primary AT port since it technically speaks AT.

1 files changed, 7 insertions, 0 deletions

diff --git a/plugins/sierra/mm-plugin-sierra.c b/plugins/sierra/mm-plugin-sierra.c
index fc39b76e..76ae323e 100644
--- a/plugins/sierra/mm-plugin-sierra.c
+++ b/plugins/sierra/mm-plugin-sierra.c
@@ -96,6 +96,13 @@ gcap_ready (MMAtSerialPort *port,
             mm_port_probe_set_result_at (ctx->probe, FALSE);
             ctx->retries = 0;
         }
+        /* Some Icera-based devices (eg, USB305) have an AT-style port that
+         * replies to everything with ERROR, so tag as unsupported; sometimes
+         * the real AT ports do this too, so let a retry tag the port as
+         * supported if it responds correctly later. */
+        else if (g_error_matches (error, MM_MOBILE_EQUIPMENT_ERROR, MM_MOBILE_EQUIPMENT_ERROR_UNKNOWN)) {
+            mm_port_probe_set_result_at (ctx->probe, FALSE);
+        }
 
         /* Just retry... */
         sierra_custom_init_step (ctx);