分享一个android手机开不了机的问题

          前段时间开发了一个小屏的功能(效果图如下:),果了一段时间,测试的人员说我们的手机有时开机不了:一直停止在开机的界面.刚开始都不知道什么原因.查了各种代码都没有发现问题.到后来感觉问题越来越严重了.

        到后来感觉问题越来越严重了.重要的是这个时低概率事件,很难复现一次,所以有点难.好不容易出现,通过data/anr/traces.txt找到问题,下面来看看关键信息:

"WindowManag4 MONITOR
  | group="main" sCount=1 dsCount=0 obj=0x4275d4d8 self=0x57929cb0
  | sysTid=732 nice=-4 sched=0/0 cgrp=apps handle=1469227632
  | schedstat=( 1563495873 1380427864 20236 )
  - waiting to lock <0x427e72d8> (a Ljava/lang/Object; ) held by tid=1 (main)
| [0]:<0006> Landroid/hardware/display/DisplayManagerGlobal;.getDisplayInfo(I)Landroid/view/DisplayInfo; (<span style="color:#FF0000;">DisplayManagerGlobal.java:108</span>)
| [1]:<0008> Landroid/view/Display;.updateDisplayInfoLocked()V (Display.java:657)
| [2]:<0002> Landroid/view/Display;.getMetrics(Landroid/util/DisplayMetrics;)V (Display.java:585)
| [3]:<0104> Lcom/android/server/display/xunhuOverlayDisplayAdapter;.<init>(Lcom/android/server/display/DisplayManagerService$SyncRoot;Lan (<span style="color:#FF0000;">xunhuOverlayDisplayAdapter.java:104</span>)
| [4]:<0030> Lcom/android/server/display/DisplayManagerService;.register_xunhuOverlayDisplayAdapterLocked()V (DisplayManagerService.java:994)

"main" prio=5 tid=1 MONITOR
  | group="main" sCount=1 dsCount=0 obj=0x422c6cf8 self=0x4182e500
  | sysTid=715 nice=-2 sched=0/0 cgrp=apps handle=1074631044
  | schedstat=( 7254851604 2756007452 25767 )
  - waiting to lock <0x4277acc8> (a Lcom/android/server/display/DisplayManagerService$SyncRoot; ) held by tid=14 (WindowManager)
| [0]:<0020> Lcom/android/server/display/DisplayManagerService;.getDisplayInfo(I)Landroid/view/DisplayInfo; (<span style="color:#FF0000;">DisplayManagerService.java:449</span>)
| [1]:<0012> Landroid/hardware/display/DisplayManagerGlobal;.getDisplayInfo(I)Landroid/view/DisplayInfo; (<span style="color:#FF0000;">DisplayManagerGlobal.java:117</span>)
| [2]:<0000> Landroid/hardware/display/DisplayManagerGlobal;.getCompatibleDisplay(ILandroid/view/DisplayAdjustments;)Landroid/view/Display; (DisplayManagerGlobal.java:176)

    public DisplayInfo getDisplayInfo(int displayId) {
        try {
            synchronized (mLock) {<span style="color:#FF0000;">//108</span>
                DisplayInfo info;
                if (USE_CACHE) {
                    info = mDisplayInfoCache.get(displayId);
                    if (info != null) {
                        return info;
                    }
                }
                info = mDm.getDisplayInfo(displayId);<span style="color:#FF0000;">//117</span>
                if (info == null) {
                    return null;
                }

    public DisplayInfo getDisplayInfo(int displayId) {
        final int callingUid = Binder.getCallingUid();
        final long token = Binder.clearCallingIdentity();
        try {
            synchronized (mSyncRoot) {<span style="color:#FF0000;">//449</span>
                /// M:[SmartBook]Ignore extra display devicee info
                if (FeatureOption.MTK_SMARTBOOK_SUPPORT) {
                    if (displayId == mExtraDisplayId) {
                        return null;
                    }
                }

    而我开发的小屏功能在DisplayManagerService里面register小屏的DisplayAdapter的时候已经获取了mSyncRoot锁,所以如果在这同时(register小屏的DisplayAdapter的时候)调用下面的代码:

        WindowManager wm = (WindowManager)context.getSystemService(Context.WINDOW_SERVICE);
        wm.getDefaultDisplay().getMetrics(metric);