Lack of input on --display 2/DeX mode

[lovintoja]

• OS: Windows
• scrcpy version: 1.12.1
• installation method: Windows release
• device model: S8+
• Android version: 9.0

So, I've just downloaded latest stable release, paste'd scrcpy and scrcpy-server from dev branch (as posted in another issue), and wanted to test it with my DeX, so basically hook my S8+ to the docking station and share input of my notebook to the desktop mode of my phone. Dumpsys shows 3 displays: 0 - internal, 2 - desktop mode (DeX), 10 - marked as HDMI output (shown only when hooked to docking station, has mHasContent=false).

Choosing --display 0 without any problems. When I write --display 2 and try to give any input, I get "CANNOT ASSOCIATE A DISPLAY ID TO THE INPUT EVENT". --display 10 shows nothing, as expected.

[rom1v]

Réf: #1177 (comment)

@peanutwolf Since the setDisplayId() method is not available before Android 10:

scrcpy/server/src/main/java/com/genymobile/scrcpy/wrappers/InputManager.java

Lines 50 to 60 in eb8f7a1

	public static boolean setDisplayId(InputEvent inputEvent, int displayId) {
	try {
	Method method = getSetDisplayIdMethod();
	method.invoke(inputEvent, displayId);
	return true;
	} catch (InvocationTargetException | IllegalAccessException | NoSuchMethodException e) {
	// just a warning, it might happen on old devices
	Ln.w("Cannot associate a display id to the input event");
	return false;
	}
	}

I think that supportsInputEvents() should just just return Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q (whatever the presentation flag):

scrcpy/server/src/main/java/com/genymobile/scrcpy/Device.java

Lines 118 to 123 in eb8f7a1

	public boolean supportsInputEvents() {
	if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
	return true;
	}
	return !isPresentationDisplay;
	}

What do you think?

Also, when not supported, I'm not sure we should disable "power mode":

scrcpy/server/src/main/java/com/genymobile/scrcpy/Controller.java

Lines 115 to 119 in eb8f7a1

	case ControlMessage.TYPE_SET_SCREEN_POWER_MODE:
	if (device.supportsInputEvents()) {
	device.setScreenPowerMode(msg.getAction());
	}
	break;

[peanutwolf]

@rom1v if supportsInputEvents() will return only Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q when on device with API lower then 29 and displays that has FLAG_PRESENTATION touch events will be forwarded on wrong display.
AOSP doc clearly states that input events can't be forwarded on external displays until API 29.

My guess that we should attempt to call setDisplayId only on SDK >= Q

@lovintoja

share input of my notebook to the desktop mode of my phone

I couldn't clearly understand how it works. Without scrcpy you connect some kind of touch screen to DeX?

[rom1v]

@peanutwolf What about something like 0e27256?

[peanutwolf]

@peanutwolf What about something like 0e27256?

Yes, correct

[rom1v]

Android version: 9.0

OK, so to summarize: input events on secondary displays may not work before Android 10.

However, they were not disabled explicitly in your case, this is fixed by 94a7f1a.