mbm: don't flash serial ports on disconnect (bgo #650740)

The F5521gw resets various port properties like echo when the port
is flashed, which was happening on disconnect.  Since MM had already
turned of echo with ATE0, and the AT parser in-use expected no
echo, this confused MM when the port magically started echoing commands
back.  We don't need flashing on the Ericsson devices because there
will always be a free AT port even if PPP is used for a secondary
PDP context, so we can just skip flashing entirely for these
devices.

1 files changed, 23 insertions, 6 deletions

diff --git a/plugins/mm-modem-mbm.c b/plugins/mm-modem-mbm.c
index 70faef42..7aa8a019 100644
--- a/plugins/mm-modem-mbm.c
+++ b/plugins/mm-modem-mbm.c
@@ -437,18 +437,28 @@ mbm_emrdy_done (MMAtSerialPort *port,
                 gpointer user_data)
 {
     MMCallbackInfo *info = user_data;
+    MMModemMbmPrivate *priv;
 
     /* If the modem has already been removed, return without
      * scheduling callback */
     if (mm_callback_info_check_modem_removed (info))
         return;
 
-    if (g_error_matches (error, MM_SERIAL_ERROR, MM_SERIAL_ERROR_RESPONSE_TIMEOUT))
-        mm_warn ("timed out waiting for EMRDY response.");
-    else {
-        MMModemMbmPrivate *priv = MM_MODEM_MBM_GET_PRIVATE (info->modem);
-
-        priv->have_emrdy = TRUE;
+    /* EMRDY unsolicited response might have happened between the command
+     * submission and the response.  This was seen once:
+     *
+     * (ttyACM0): --> 'AT*EMRDY?<CR>'
+     * (ttyACM0): <-- 'T*EMRD<CR><LF>*EMRDY: 1<CR><LF>Y?'
+     *
+     * So suppress the warning if the unsolicited handler handled the response
+     * before we get here.
+     */
+    priv = MM_MODEM_MBM_GET_PRIVATE (info->modem);
+    if (!priv->have_emrdy) {
+        if (g_error_matches (error, MM_SERIAL_ERROR, MM_SERIAL_ERROR_RESPONSE_TIMEOUT))
+            mm_warn ("timed out waiting for EMRDY response.");
+        else
+            priv->have_emrdy = TRUE;
     }
 
     do_init (port, info);
@@ -966,6 +976,13 @@ grab_port (MMModem *modem,
     if (port && MM_IS_AT_SERIAL_PORT (port)) {
         GRegex *regex;
 
+        /* The Ericsson modems always have a free AT command port, so we
+         * don't need to flash the ports when disconnecting to get back to
+         * command mode.  F5521gw R2A07 resets port properties like echo when
+         * flashed, leading to confusion.  bgo #650740
+         */
+        g_object_set (G_OBJECT (port), MM_SERIAL_PORT_FLASH_OK, FALSE, NULL);
+
         if (ptype == MM_PORT_TYPE_PRIMARY) {
             regex = g_regex_new ("\\r\\n\\*E2NAP: (\\d)\\r\\n", G_REGEX_RAW | G_REGEX_OPTIMIZE, 0, NULL);
             mm_at_serial_port_add_unsolicited_msg_handler (MM_AT_SERIAL_PORT (port), regex, mbm_e2nap_received, modem, NULL);