huawei: avoid AT^GETPORTMODE in Huawei MU609

The MU609 modems from Huawei have a bug (confirmed by Huawei) that causes
the modem to reset if AT^GETPORTMODE is issued.

I have provided and example udev rule I use to disable this command as a
patch,  feel free to drop that if its not acceptable.  Since I cannot tell
the modem type from within the udev rules this is less specific than my
previous code based patch,  but much simpler ;-)

I have two modems that share the same USB ID,  however,  neither supports the
^GETPORTMODE command (and one of them crashes when it is issued).  Perhaps
someone with a Huawei that supports ^GETPORTMODE can check their USB ID's
and see if they clash.

Here is a comment from the Huawei devs:
> We confirmed this is a issue. This is Qualcomm baseband command at Data
> Card. We didn’t delete and block it. We will fix this issue in next FW.
> Thank you very much.

Sign-off-by: David McCullough <david.mccullough@accelecon.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/plugins/huawei/mm-plugin-huawei.c b/plugins/huawei/mm-plugin-huawei.c
index 26191a61..c9b923e4 100644
--- a/plugins/huawei/mm-plugin-huawei.c
+++ b/plugins/huawei/mm-plugin-huawei.c
@@ -250,6 +250,7 @@ static void
 huawei_custom_init_step (HuaweiCustomInitContext *ctx)
 {
     FirstInterfaceContext *fi_ctx;
+    GUdevDevice *port;
 
     /* If cancelled, end */
     if (g_cancellable_is_cancelled (ctx->cancellable)) {
@@ -286,7 +287,8 @@ huawei_custom_init_step (HuaweiCustomInitContext *ctx)
     }
 
     /* Try to get a port map from the modem */
-    if (!ctx->getportmode_done) {
+    port = mm_port_probe_peek_port (ctx->probe);
+    if (!ctx->getportmode_done && !g_udev_device_get_property_as_boolean (port, "ID_MM_HUAWEI_DISABLE_GETPORTMODE")) {
         if (ctx->getportmode_retries == 0) {
             g_simple_async_result_set_op_res_gboolean (ctx->result, TRUE);
             huawei_custom_init_context_complete_and_free (ctx);