Back in 2017, when I got my first Android TV device (original Xiaomi Mi Box or MIBOX3), I made a bug report at Issue Tracker website on 09/21/17 because the device didn't "wake up" by using the "Chromecast Built-in".
On the next day, they replied by closing the report as "Won't Fix (Intended Behavior)" along with this message:
"Thanks for reporting the issue. This feature is not officially supported by us yet and our team is working on it. However, there are few OEM's support from their side. We are not sure whether Xiaomi Mi Box supports or not. We would recommend you to check with Xiaomi Mi Box technical support team on this"
It's been 1080 days, and the "Wake on LAN" feature is still not widely available on ALL Android TV devices, so, what I request to all of you is to go that Issue Tracker report to put more pressure on Google about this so needed feature. Remember, the more people reply, the merrier.
Thanks in advance.
SOLUTION AND TIPS
Problem - TV goes into deep sleep during night, resetting all running apps and active state. Also disabling Chromecast until you run TV next time.
Because Android TV (at least my Philips) does some night maintenance cycles, during which it checks for firmware updates, rescan TV stations and mainly closes all running apps, reset last state and run TV in TV mode. Also seems to disable Google Chrome module, which appears again only after powering TV. All this work flawlessly during day, had no problems quickly resuming TV was already powered on. But it is reset again during night, so starting TV next day takes about 20-30s a you have to run your apps again. If it only sleeps, power-on takes 5s and you end up in app you used last, not in TV module. I dont even have antenna connected, so why bother.
What I tried first was disabling all green power-saving crap in settings, but it didnt help:
Settings>Eco settings>Switch off timer = 0 (disabled)
Settings>Eco settings>Energy savings = OFF (but doubt that it has anything with sleep)
Settings>Wireless and networks>Wired or wifi>Switch on with wifi = ON
Settings>Wireless and networks>Wired or wifi>Switch on with Chromecast = ON
Only working way I found for deep sleep problem is using Wakelock Revamped. It is on Play store, but not compatible with Android TV. So you have to sideload APK using flashdisk and any working file manager (Solid or X-Plore are TV compatible). You can download latest version of APK from developer Github. What this app does is keep wakelock or state of CPU/WiFi component out of sleep. Which is crucial, because then system doesn't run night cycles and your TV is powered much faster.
Tip for running it on TV as it seems to be setup as system app, not directly supporting Android TV, you wont find it in installed apps. Found workaround how to run it, go to:
Settings -> Android settings -> Device preferences -> Storage -> Internal storage -> Apps -> See all apps -> scroll to bottom System apps -> scroll down to Wakelock v3 and click -> Open. Voila. Great UX!
Here are the settings of Wakelock
Screen with Wakelock Revamped settings
And I tested so far:
CPU + WiFi normal wakelock - no reset during night, Chromecast running in the morning
WiFi Normal wakelock only - no reset during night, Chromecast missing (have to run TV)
WIFI high performance only - reset during night
CPU wakelock only - reset during night
Notes and concerns
- testing is done on 65PUS7304/12, its midrange from last year.
- as all testing is done in day cycles, you have to wait over night, it is hard to get more results. Feel free to help me testing your TV, preferably Philips.
- have to get some wattmeter to see what is the difference, hope it doesnt take much more power. But its "mobile" CPU, it shouldnt.
- not sure if this problem is Philips specific, had nice chat with their tech guy and he explained me stuff about night cycle and that its probably Android TV thing. If it is true, great UX Google...