stay-awake flag doesn't work when device isn't charging

[Matthbo]

• I have read the FAQ.
• I have searched in existing issues.

Environment

• OS: Windows 10
• scrcpy version: 1.14
• installation method: Windows x64 zip
• device model: Xiaomi Mi A1
• Android version: 9

Describe the bug
The screen won't stay awake as the flag suggests, unless the device is charging

Using commands:

./scrcpy -Sw
# or
./scrcpy -w
# or
./scrcpy --stay-awake

Expected behaviour:
The screen will stay awake, even if the device isn't charging

[rom1v]

That is correct. Btw, the Android option is called stay_on_while_plugged_in.

I just added this limitation to the documentation: 0e4a6f4

AFAIK, there is no way to "stay awake" while the device is unplugged with an Android setting (without a separate app taking a wake lock, with its own limitations).

[Matthbo]

Ah okay, that makes sense

[jsuelwald]

I'd like to re-open this ticket and would like to have "stay awake even while not charging" as a feature.

Reason: If other apps can do this, why can't scrcpy do this as well?

[rom1v]

Reason: If other apps can do this, why can't scrcpy do this as well?

Because (at least for now) the device side of scrcpy is not an Android app. But even if it was, I'm not sure you can hold a wakelock if you are not the app with an activity in the background.

[Pawloland]

@rom1v
Obligatory sorry for ping.
I was searching for a way to make --staye-awake work when connecting through wifi and found one.
As you said there isn't any way to make stay_on_while_plugged_in respected when device isn't connected.
However there is a way to mock the state of the device being plugged in. How to do it via adb:

• mocking device being plugged in and charging (in my tests it was better to also mock charging because the first one alone sometimes isn't sufficient on specific devices) EDIT: the second one seems to be redundant after all, sorry for misinformation. Also keep in mind that while this workaround works it has one drawback - systemui stops displaying correct battery percentage (it freezes on the value displayed at the time of executing the command), so it's hard to guess what percentage is left. As a workaround for this issue we could write a script that periodically quickly resets changes with the last command and then instantly sets them again. This would limit the stuck percentage value bug to a small extent. Given how often it would trigger, the lesser "stuck percentages" would happen.

  adb shell dumpsys battery set ac 1                 # mocks being connected to power source
  adb shell dumpsys battery set status 2             # mocks device charging
  

• starting scrcpy with our flag

  scrcpy  --staye-awake
  

• after disconnecting resetting our mocked state to reflect a real situation

   adb shell dumpsys battery reset
  

With this method the device won't go to sleep. It could be implemented directly inside scrcpy. Whenever we would connect through wifi with --staye-awake flag set, scrcpy would automatically mock battery state. After disconnecting it would automatically revert those changes, so device wouldn't be stuck in this strange state where it says it is charging while actually discharging.
I lack the skills to make a PR myself so I leave it here, hoping someday it will be implemented. By that time anyone can use it manually like in the example above. Just remember to manually reset changes after ending using scrcpy.
More about it can be found here.

[ahmed98Osama]

#1445 (comment)

a Very good trick from @Pawloland
i love it and it is working 😍