Kill wpa_supplicant before load driver

When system_server restarts due to crash,
the start sequence for wifi is as follows:
1.) unload wifi driver
2.) load wifi driver
3.) kill wpa_supplicant that was left
4.) start new wpa_supplicant

The problem is that when we load the wifi driver,
the old wpa_supplicant will be notified immediatedly
due to netlink, and tries to bring up the interface
This is unnecessary.

We should kill wpa_supplicant before loading wifi driver
to avoid unnecessary bring up of interface by old wpa_supplicant
and possibly race condition in kernel driver.

Change-Id: Ie39c9b847d811e09c55386c1c4cf5f554af05868

1 files changed, 6 insertions, 6 deletions

diff --git a/service/java/com/android/server/wifi/WifiStateMachine.java b/service/java/com/android/server/wifi/WifiStateMachine.java
index d3beaa8d6..21e58c27d 100644
--- a/service/java/com/android/server/wifi/WifiStateMachine.java
+++ b/service/java/com/android/server/wifi/WifiStateMachine.java
@@ -4453,6 +4453,12 @@ public class WifiStateMachine extends StateMachine implements WifiNative.WifiRss
             logStateAndMessage(message, this);
             switch (message.what) {
                 case CMD_START_SUPPLICANT:
+                   /* Stop a running supplicant after a runtime restart
+                    * Avoids issues with drivers that do not handle interface down
+                    * on a running supplicant properly.
+                    */
+                    mWifiMonitor.killSupplicant(mP2pSupported);
+
                     if (mWifiNative.loadDriver()) {
                         try {
                             mNwService.wifiFirmwareReload(mInterfaceName, "STA");
@@ -4485,12 +4491,6 @@ public class WifiStateMachine extends StateMachine implements WifiNative.WifiRss
                             loge("Unable to change interface settings: " + ie);
                         }
 
-                       /* Stop a running supplicant after a runtime restart
-                        * Avoids issues with drivers that do not handle interface down
-                        * on a running supplicant properly.
-                        */
-                        mWifiMonitor.killSupplicant(mP2pSupported);
-
                         if (mWifiNative.startHal() == false) {
                             /* starting HAL is optional */
                             loge("Failed to start HAL");