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Why does my device screen goes black when starting Knox Container Only Mode (COM)

 
[Environment]
Samsung Android M OS devices configured to be in Knox Container Only Mode (COM).

[Issue]
When turning on the device in COM mode, I see a black screen instead of the expected lock screen. Key presses are non responsive.

[Causes]
If the COM lock type is Fingerprint this can happen if the system is busy beyond 5 seconds which results in a ANR (App not responding) crash in the Main process thread. This also results in an ANR crash for the fingerprint process. You may notice the following type of log entries.

Process: com.samsung.knox.kss
Flags: 0x38d8be45
Package: com.samsung.knox.kss
Build: samsung/heroltexx/herolte:6.0.1/MMB29K/G930FXXU1BPH6:user/release-keys
Subject: Input dispatching timed out (Waiting to send non-key event because the touched window has not finished processing certain input events that were delivered to it over 500.0ms ago.  Wait queue length: 26.  Wait queue head age: 11261.4ms.)
'main' prio=5 tid=1 Runnable
  | group='main' sCount=0 dsCount=0 obj=0x77283308 self=0x7fa22f4a00
  | sysTid=5073 nice=0 cgrp=default sched=0/0 handle=0x7fa622d1d0
  | state=R schedstat=( 2037142500707 85854614269 4400976 ) utm=141241 stm=62473 core=2 HZ=100
  | stack=0x7ffd9e4000-0x7ffd9e6000 stackSize=8MB
  | held mutexes= 'mutator lock'(shared held)
  at android.hardware.display.IDisplayManager$Stub$Proxy.getDisplayInfo(IDisplayManager.java:681)
  at android.hardware.display.DisplayManagerGlobal.getDisplayInfo(DisplayManagerGlobal.java:191)
  - locked <0x0007f40e> (a java.lang.Object)
  at android.hardware.display.DisplayManagerGlobal.getDisplayInfo(DisplayManagerGlobal.java:166)
  at android.hardware.display.DisplayManagerGlobal.getDisplayInfo(DisplayManagerGlobal.java:159)
  at android.view.Display.updateDisplayInfoLocked(Display.java:947)
  at android.view.Display.updateDisplayInfoLocked(Display.java:933)
  at android.view.Display.getRotation(Display.java:670)
  - locked <0x00935e2f> (a android.view.Display)
  at com.samsung.knox.kss.KnoxKeyguardFingerprintView.updateOrientation(KnoxKeyguardFingerprintView.java:135)
  at com.samsung.knox.kss.KnoxKeyguardFingerprintView.access$100(KnoxKeyguardFingerprintView.java:49)
  at com.samsung.knox.kss.KnoxKeyguardFingerprintView$2.onOrientationChanged(KnoxKeyguardFingerprintView.java:172)
  at android.view.OrientationEventListener$SensorEventListenerImpl.onSensorChanged(OrientationEventListener.java:456)
  at android.hardware.SystemSensorManager$SensorEventQueue.dispatchSensorEvent(SystemSensorManager.java:583) 


# 2. If the Lock screen has a custom wallpaper, it can use too much memory when the device is started in the COM mode. This result in an 'out of memory' error. You may have the following log entry in the device log.

com.samsung.rcs.framework.instantmessaging.action.OUT_OF_MEMORY_ERROR

[Resolution]
Both of the above root causes have been fixed in different software versions for different devices. If you have identified which of the root cause applies to you, please contact us by logging in and creating a ticket @ www.samsungknox.com and we can verify the fix availability for your device.


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