broadband-modem-qmi: don't always trust the current capabilities reported by SSP

Sometimes the 'Mode Preference' TLV in the SSP response will have incorrect
values. The following log is for a Gobi3k modem which is *only* GMS/UMTS.

ModemManager[13415]: [/dev/cdc-wdm0] Received message...
>>>>>> QMUX:
>>>>>>   length  = 44
>>>>>>   flags   = 0x80
>>>>>>   service = "nas"
>>>>>>   client  = 2
>>>>>> QMI:
>>>>>>   flags       = "response"
>>>>>>   transaction = 1
>>>>>>   tlv_length  = 32
>>>>>>   message     = "Get System Selection Preference" (0x0034)
>>>>>> TLV:
>>>>>>   type       = "Result" (0x02)
>>>>>>   length     = 4
>>>>>>   value      = 00:00:00:00
>>>>>>   translated = SUCCESS
>>>>>> TLV:
>>>>>>   type       = "Emergency mode" (0x10)
>>>>>>   length     = 1
>>>>>>   value      = 00
>>>>>>   translated = 0
>>>>>> TLV:
>>>>>>   type       = "Mode Preference" (0x11)
>>>>>>   length     = 2
>>>>>>   value      = 0F:00
>>>>>>   translated = 15
>>>>>> TLV:
>>>>>>   type       = "Band Preference" (0x12)
>>>>>>   length     = 8
>>>>>>   value      = FF:FF:FF:3F:FF:FF:FF:FF
>>>>>>   translated = 18446744070488326143
>>>>>> TLV:
>>>>>>   type       = "Roaming Preference" (0x14)
>>>>>>   length     = 2
>>>>>>   value      = FF:00
>>>>>>   translated = 255

Instead of setting to '1' only the bits related to GSM/UMTS in the "Mode
Preference" TLV, the modem sets all the bits it knows of to '1', including the
CDMA/EVDO ones. It is not easy to detect this properly, because the modem didn't
set to '1' the bits it didn't know of (e.g. LTE or TD-SCDMA), so we *cannot*
assume that 0x000F actually means 'unknown'.

So, we now will pass these returned values through the "DMS Get Capabilities"
filter, as we did for the Technology Preference result. The final reported
current capabilities will be either:
 * The intersection between the capabilities loaded by "NAS Get System Selection
   Preference" and "DMS Get Capabilities" or,
 * The intersection between the capabilities loaded by "NAS Get Technology
   Preference" and "DMS Get Capabilities".

For 'modem' (not 'current') capabilities, we still rely only on "DMS Get
Capabilities".

1 files changed, 32 insertions, 38 deletions

diff --git a/src/mm-broadband-modem-qmi.c b/src/mm-broadband-modem-qmi.c
index c19f104c..11f697a1 100644
--- a/src/mm-broadband-modem-qmi.c
+++ b/src/mm-broadband-modem-qmi.c
@@ -154,7 +154,6 @@ modem_create_bearer (MMIfaceModem *self,
 /*****************************************************************************/
 /* Current Capabilities loading (Modem interface) */
 
-
 typedef struct {
     MMBroadbandModemQmi *self;
     QmiClientNas *nas_client;
@@ -163,6 +162,7 @@ typedef struct {
     gboolean run_get_system_selection_preference;
     gboolean run_get_technology_preference;
     gboolean run_get_capabilities;
+    MMModemCapability capabilities;
 } LoadCurrentCapabilitiesContext;
 
 static MMModemCapability
@@ -203,7 +203,6 @@ load_current_capabilities_get_capabilities_ready (QmiClientDms *client,
                                                   GAsyncResult *res,
                                                   LoadCurrentCapabilitiesContext *ctx)
 {
-    MMModemCapability caps = MM_MODEM_CAPABILITY_NONE;
     QmiMessageDmsGetCapabilitiesOutput *output = NULL;
     GError *error = NULL;
 
@@ -235,22 +234,20 @@ load_current_capabilities_get_capabilities_ready (QmiClientDms *client,
         }
 
         /* Final capabilities are the intersection between the Technology
-         * Preference (ie, allowed modes) and the device's capabilities.  If
-         * the Technology Preference was "auto" or unknown we just fall back to
-         * the Get Capabilities response.
+         * Preference (ie, allowed modes) or SSP and the device's capabilities.
+         * If the Technology Preference was "auto" or unknown we just fall back
+         * to the Get Capabilities response.
          */
-        caps = ((MMModemCapability) GPOINTER_TO_UINT (
-                    g_simple_async_result_get_op_res_gpointer (ctx->result)));
-        if (caps == MM_MODEM_CAPABILITY_NONE)
-            caps = mask;
+        if (ctx->capabilities == MM_MODEM_CAPABILITY_NONE)
+            ctx->capabilities = mask;
         else
-            caps &= mask;
+            ctx->capabilities &= mask;
     }
 
     if (output)
         qmi_message_dms_get_capabilities_output_unref (output);
 
-    g_simple_async_result_set_op_res_gpointer (ctx->result, GUINT_TO_POINTER (caps), NULL);
+    g_simple_async_result_set_op_res_gpointer (ctx->result, GUINT_TO_POINTER (ctx->capabilities), NULL);
     load_current_capabilities_context_complete_and_free (ctx);
 }
 
@@ -259,7 +256,6 @@ load_current_capabilities_get_technology_preference_ready (QmiClientNas *client,
                                                            GAsyncResult *res,
                                                            LoadCurrentCapabilitiesContext *ctx)
 {
-    MMModemCapability caps = MM_MODEM_CAPABILITY_NONE;
     QmiMessageNasGetTechnologyPreferenceOutput *output = NULL;
     GError *error = NULL;
 
@@ -279,24 +275,24 @@ load_current_capabilities_get_technology_preference_ready (QmiClientNas *client,
             NULL, /* duration */
             NULL);
         if (preference_mask != QMI_NAS_RADIO_TECHNOLOGY_PREFERENCE_AUTO) {
-            caps = mm_modem_capability_from_qmi_radio_technology_preference (preference_mask);
-            if (caps == MM_MODEM_CAPABILITY_NONE) {
-                gchar *str;
+            gchar *str;
 
-                str = qmi_nas_radio_technology_preference_build_string_from_mask (preference_mask);
-                mm_dbg ("Unsupported modes reported: '%s'", str);
-                g_free (str);
-            }
+            str = qmi_nas_radio_technology_preference_build_string_from_mask (preference_mask);
+            ctx->capabilities = mm_modem_capability_from_qmi_radio_technology_preference (preference_mask);
+            mm_dbg ("%s modes reported in technology preference: '%s'",
+                    ctx->capabilities == MM_MODEM_CAPABILITY_NONE ? "Unsupported" : "Valid",
+                    str);
+            g_free (str);
         }
     }
 
     if (output)
         qmi_message_nas_get_technology_preference_output_unref (output);
 
+    /* Mark as TP already run */
     ctx->run_get_technology_preference = FALSE;
 
     /* Get DMS Capabilities too */
-    g_simple_async_result_set_op_res_gpointer (ctx->result, GUINT_TO_POINTER (caps), NULL);
     load_current_capabilities_context_step (ctx);
 }
 
@@ -305,7 +301,6 @@ load_current_capabilities_get_system_selection_preference_ready (QmiClientNas *c
                                                                  GAsyncResult *res,
                                                                  LoadCurrentCapabilitiesContext *ctx)
 {
-    MMModemCapability caps = MM_MODEM_CAPABILITY_NONE;
     QmiMessageNasGetSystemSelectionPreferenceOutput *output = NULL;
     GError *error = NULL;
     QmiNasRatModePreference mode_preference_mask = 0;
@@ -323,29 +318,27 @@ load_current_capabilities_get_system_selection_preference_ready (QmiClientNas *c
                    NULL)) {
         mm_dbg ("Mode preference not reported in system selection preference");
     } else {
-        caps = mm_modem_capability_from_qmi_rat_mode_preference (mode_preference_mask);
-        if (caps == MM_MODEM_CAPABILITY_NONE) {
-            gchar *str;
-
-            str = qmi_nas_rat_mode_preference_build_string_from_mask (mode_preference_mask);
-            mm_dbg ("Unsupported capabilities reported: '%s'", str);
-            g_free (str);
-        }
+        gchar *str;
+
+        str = qmi_nas_rat_mode_preference_build_string_from_mask (mode_preference_mask);
+        ctx->capabilities = mm_modem_capability_from_qmi_rat_mode_preference (mode_preference_mask);
+        mm_dbg ("%s capabilities reported in system selection preference: '%s'",
+                ctx->capabilities == MM_MODEM_CAPABILITY_NONE ? "Unsupported" : "Valid",
+                str);
+        g_free (str);
     }
 
     if (output)
         qmi_message_nas_get_system_selection_preference_output_unref (output);
 
-    if (caps == MM_MODEM_CAPABILITY_NONE) {
-        /* Fall back to Technology Preference */
-        ctx->run_get_system_selection_preference = FALSE;
-        load_current_capabilities_context_step (ctx);
-        return;
-    }
+    /* Mark as SSP already run */
+    ctx->run_get_system_selection_preference = FALSE;
 
-    /* Success */
-    g_simple_async_result_set_op_res_gpointer (ctx->result, GUINT_TO_POINTER (caps), NULL);
-    load_current_capabilities_context_complete_and_free (ctx);
+    /* If we got some value, cache it and go on to DMS Get Capabilities */
+    if (ctx->capabilities != MM_MODEM_CAPABILITY_NONE)
+        ctx->run_get_technology_preference = FALSE;
+
+    load_current_capabilities_context_step (ctx);
 }
 
 static void
@@ -435,6 +428,7 @@ modem_load_current_capabilities (MMIfaceModem *self,
                                              callback,
                                              user_data,
                                              modem_load_current_capabilities);
+    ctx->capabilities = MM_MODEM_CAPABILITY_NONE;
 
     /* System selection preference introduced in NAS 1.1 */
     ctx->run_get_system_selection_preference = qmi_client_check_version (nas_client, 1, 1);