Screen on not working on Samsung Tab A

[paulsiu]

On a Samsung Tab A, the screen eventually turns blank after a display timeout. When I attempt to access the tablet via anydesk or teamviewer unattended, the screen is blank and connecting to it does not wake it up. To get around this issue, I call the tablet using Google DUO. This cause it to display a screen to accept calls, which wakes up the screen. As to why I need to remote to the tablet, it's to support a tech challenged family member.

The problem with using DUO is that it rings the tablet. I created a Macdroid where it would do a screen on when Anydesk is open. Unfortunately, this does not wake up the screen, neither does the alternate method of screen on. I also set it up to wake up for several minutes, but that did not work either. How can I wake up the tablet?

 

[Jacob L]

Trigger: webhook
Action: screen on

 

[paulsiu]

Thank you.

The issue is not that screen on is not trigger, but that screen on does not actually turn the tablet's screen back on. For example, I did the following experiment where I create a separate webhook for each action:
* Screen on
* Screen Wake
* Screen Off
* take a picture

In all cases, calling the webhook triggered the action when the tablet screen is on and unlocked. If I wait an hour or so, the tablet will lock and the screen will become blank when I login using anydesk and remains so even if I call the 4 webhooks. There is still network connectivity since I am able to connect using any desk but it's just that I can't do anything else because I cannot wake up the screen.

 

[paulsiu]

I notice that the tablet seems to experience different level of sleep. Initially, when the screen locks and you connect using anydesk or Teamviewer, the screen wakes immediately. If it does not, you can use anydesk's keyboard shortcut for home and keep pressing it a few times to wake it up. The webhook calls also work.

Wait a few hours and the tablet seems to become totally unresponsive. However, it is accepting connection from anydesk so it must be still accepting network connection. However, it no longer response to input, and calling the webhooks does nothing. However, I did notice that repeated calls to screen on using webhook, if repeated multiple times will wake up the screen. If I call the webhook to turn on screen 5 or 6 times, it will actually wake. I have to experiment some more and report back.

 

[MacroDroidDev]

It sounds like that the tablet is going into some kind of hardcore doze mode where it just wont turn on the screen unless you physically press the button. This kind of makes sense for a tablet as it's the sort of device that you might put down and pick up a few days later and it's really annoying if the battery has gone down significantly.

If you haven't already I would suggest a good read through https://dontkillmyapp.com/samsung and maybe google around for specifics on this tablet to see if there is any way this behaviour can be stopped, or maybe disabled for certain apps.

 

[paulsiu]

The issue turned out to be caused by the proximity sensor. I had the samsung tablet set to stay awake in developer mode. I can see the cursor moving around, but the screen is blank. It turns out that the tablet has a smart cover and when you close it, the magnet triggers the proximity sensor which then blanks out the screen.

 

[Jacob L]

I think you can turn off smart cover. You'd have to play round with the settings