Crash when Fully External Display Mode is enabled in Galaxy screen mirroring mode

[bynkook]

After a recent Galaxy S25+ firmware update, Artemis crashes only when Fully External Display Mode is enabled.

Important observations:

• If Fully External Display Mode is disabled, streaming still starts and connects normally.
• In that disabled state, the stream is displayed only in part of the external monitor instead of filling it.
• Samsung DeX screen extension mode also works; Artemis appears in a window and does not crash.
• The crash happens only in Galaxy screen mirroring mode with Fully External Display Mode enabled.
• The app crashes before the streaming connection attempt actually starts.

This suggests the host PC, network, decoder, and normal streaming path are not the root cause.

The issue appears specific to the Fully External Display Mode launch path. In screen mirroring mode, the external display may no longer be a valid target for launching an Activity via ActivityOptions.setLaunchDisplayId(), even though it is exposed as a non-default display. Artemis currently seems to treat the first non-default display as a launchable secondary display, which may crash on newer Samsung firmware.

Most likely fix:

• Do not treat the first non-default display from DisplayManager.getDisplays() as a launchable secondary display.
• Prefer DisplayManager.getDisplays(DisplayManager.DISPLAY_CATEGORY_PRESENTATION) and only select displays that are valid presentation/external-display targets.
• Before calling ActivityOptions.setLaunchDisplayId(), verify that the target display can actually launch the Game activity. On supported Android versions, this can be checked with ActivityManager.isActivityStartAllowedOnDisplay().
• Wrap startActivity(gameIntent, options.toBundle()) in a try/catch for SecurityException/RuntimeException, so an invalid screen-mirroring display target falls back instead of crashing the app.
• If no launchable secondary display is available, fall back to the normal streaming path and optionally disable/fullscreen-fallback Fully External Display Mode for that session.

Device/context:

• Phone: Galaxy S25+
• External monitor connected to the phone
• Mode that works: DeX screen extension mode
• Mode that crashes: Galaxy screen mirroring mode
• Trigger: Video Settings -> Fully External Display Mode enabled

Possible area to inspect:

• Secondary display selection logic
• ActivityOptions.setLaunchDisplayId() handling
• Fallback behavior when the non-default display is not launchable

[ClassicOldSong]

Samsung modified too much things related to display, and I'm too poor to afford a Samsung phone. Anything related to Samsung will not get support until I get a Samsung as my daily driver.

[XDleader555]

Also running into the same problem on my Pixel 8 Pro. Seems like Android prefers app developers to utilize the Presentation API over ActivityManager.

https://source.android.com/docs/core/display/multi_display/activity-launch
https://developer.android.com/reference/android/app/Presentation

com.limelight.LimeLog: Display id 0: DisplayInfo{"Built-in Screen", displayId 0, displayGroupId 0, FLAG_SECURE, FLAG_SUPPORTS_PROTECTED_BUFFERS, FLAG_TRUSTED, FLAG_ALLOWS_CONTENT_MODE_SWITCH, real 1344 x 2992, largest app 2992 x 2992, smallest app 1344 x 1344, appVsyncOff 6233334, presDeadline 11500000, mode 1, renderFrameRate 60.0, hasArrSupport false, frameRateCategoryRate FrameRateCategoryRate {normal=60.0, high=90.0}, supportedRefreshRates [60.0, 30.0, 20.0], frameRateVelocityMapping [android.view.FrameRateVelocityPoint@b9003c1, android.view.FrameRateVelocityPoint@545a03c1, android.view.FrameRateVelocityPoint@5ea603c1], defaultMode 2, userPreferredModeId 2, supportedModes [{id=1, parentModeId=-1, flags=, width=1344, height=2992, fps=60.0, vsync=60.0, alternativeRefreshRates=[120.00001], supportedHdrTypes=[2, 3, 4]}, {id=2, parentModeId=-1, flags=, width=1344, height=2992, fps=120.00001, vsync=120.00001, alternativeRefreshRates=[60.0], supportedHdrTypes=[2, 3, 4]}, {id=3, parentModeId=-1, flags=, width=1008, height=2244, fps=120.00001, vsync=120.00001, alternativeRefreshRates=[60.0], supportedHdrTypes=[2, 3, 4]}, {id=4, parentModeId=-1, flags=, width=1008, height=2244, fps=60.0, vsync=60.0, alternativeRefreshRates=[120.00001], supportedHdrTypes=[2, 3, 4]}], hdrCapabilities HdrCapabilities{mSupportedHdrTypes=[2, 3, 4], mMaxLuminance=1000.0, mMaxAverageLuminance=1000.0, mMinLuminance=5.0E-4}, isForceSdr false, userDisabledHdrTypes [], minimalPostProcessingSupported false, rotation 0, state ON, committedState ON}, DisplayMetrics{density=3.0, width=1344, height=2769, scaledDensity=3.0, xdpi=487.68, ydpi=490.301}, isValid=true
com.limelight.LimeLog: Display id 68: DisplayInfo{"SmartGlasses", displayId 68, displayGroupId 0, FLAG_SECURE, FLAG_SUPPORTS_PROTECTED_BUFFERS, FLAG_PRESENTATION, FLAG_TRUSTED, FLAG_ALLOWS_CONTENT_MODE_SWITCH, real 1920 x 1080, largest app 1920 x 1920, smallest app 1080 x 1080, appVsyncOff 6233334, presDeadline 11500000, mode 95, renderFrameRate 60.0, hasArrSupport false, frameRateCategoryRate FrameRateCategoryRate {normal=60.0, high=90.0}, supportedRefreshRates [60.0, 30.0, 20.0], frameRateVelocityMapping [], defaultMode 95, userPreferredModeId -1, supportedModes [{id=95, parentModeId=-1, flags=, FLAG_SIZE_OVERRIDE, width=1920, height=1080, fps=60.0, vsync=60.0, alternativeRefreshRates=[], supportedHdrTypes=[]}, {id=96, parentModeId=-1, flags=, FLAG_SIZE_OVERRIDE, width=1920, height=1080, fps=59.9402, vsync=59.9402, alternativeRefreshRates=[], supportedHdrTypes=[]}, {id=97, parentModeId=-1, flags=, FLAG_SIZE_OVERRIDE, width=640, height=480, fps=59.940475, vsync=59.940475, alternativeRefreshRates=[], supportedHdrTypes=[]}, {id=98, parentModeId=97, flags=, FLAG_SIZE_OVERRIDE, FLAG_ANISOTROPY_CORRECTION, width=853, height=480, fps=59.940475, vsync=59.940475, alternativeRefreshRates=[], supportedHdrTypes=[]}], hdrCapabilities HdrCapabilities{mSupportedHdrTypes=[], mMaxLuminance=500.0, mMaxAverageLuminance=500.0, mMinLuminance=0.0}, isForceSdr false, userDisabledHdrTypes [], minimalPostProcessingSupported false, rotation 0, state ON, committedState ON}, DisplayMetrics{density=0.9375, width=1920, height=1080, scaledDensity=0.9375, xdpi=50.8, ydpi=50.8}, isValid=true
ActivityTaskManager: Launch on display check: activity launch is not allowed on a display that cannot host tasks
ActivityTaskManager: Permission Denial: starting Intent { flg=0x18000000 xflg=0x4 cmp=com.limelight.noirdebug/com.limelight.Game (has extras) } from ProcessRecord{26dfaca 8288:com.limelight.noirdebug/u0a471} (pid=8288, uid=10471) with launchDisplayId=68

I've verified that creating a Presentation dialog for the external display produces the expected results (external display in mirror mode switches to max resolution and streams the video correctly).
f024635

[bynkook]

Also running into the same problem on my Pixel 8 Pro. Seems like Android prefers app developers to utilize the Presentation API over ActivityManager.

https://source.android.com/docs/core/display/multi_display/activity-launch https://developer.android.com/reference/android/app/Presentation

I've verified that creating a Presentation dialog for the external display produces the expected results (external display in mirror mode switches to max resolution and streams the video correctly). f024635

I've tested your patch with my Galaxy 25+. the patch does not produce the error and launched the game mode successfully. One thing not fixed is the mode make blank black space on left and right edges of external monitor output. I will dig more into the presentation mode. My conclusion is your patch for Fully External Display Mode is partially successful.

[XDleader555]

Also running into the same problem on my Pixel 8 Pro. Seems like Android prefers app developers to utilize the Presentation API over ActivityManager.
https://source.android.com/docs/core/display/multi_display/activity-launch https://developer.android.com/reference/android/app/Presentation
I've verified that creating a Presentation dialog for the external display produces the expected results (external display in mirror mode switches to max resolution and streams the video correctly). f024635

I've tested your patch with my Galaxy 25+. the patch does not produce the error and launched the game mode successfully. One thing not fixed is the mode make blank black space on left and right edges of external monitor output. I will dig more into the presentation mode. My conclusion is your patch for Fully External Display Mode is partially successful.

Does the toast notification show the correct external display resolution when you launch the stream?
Is the video stream resolution in the performance stats have the same as the external monitor resolution?

[bynkook]

Also running into the same problem on my Pixel 8 Pro. Seems like Android prefers app developers to utilize the Presentation API over ActivityManager.
https://source.android.com/docs/core/display/multi_display/activity-launch https://developer.android.com/reference/android/app/Presentation
I've verified that creating a Presentation dialog for the external display produces the expected results (external display in mirror mode switches to max resolution and streams the video correctly). f024635

I've tested your patch with my Galaxy 25+. the patch does not produce the error and launched the game mode successfully. One thing not fixed is the mode make blank black space on left and right edges of external monitor output. I will dig more into the presentation mode. My conclusion is your patch for Fully External Display Mode is partially successful.

Does the toast notification show the correct external display resolution when you launch the stream?

Is the video stream resolution in the performance stats have the same as the external monitor resolution?

i did another test on another monitor. the monitor output is full screen without blank space. i think it is another issue with Android native presentation mode.

the new issue is, mouse movement is not captured with the fix. I think this is gap produced by the Presentation mode either. Trying to fix this now.....

[XDleader555]

Also running into the same problem on my Pixel 8 Pro. Seems like Android prefers app developers to utilize the Presentation API over ActivityManager.
https://source.android.com/docs/core/display/multi_display/activity-launch https://developer.android.com/reference/android/app/Presentation
I've verified that creating a Presentation dialog for the external display produces the expected results (external display in mirror mode switches to max resolution and streams the video correctly). f024635

I've tested your patch with my Galaxy 25+. the patch does not produce the error and launched the game mode successfully. One thing not fixed is the mode make blank black space on left and right edges of external monitor output. I will dig more into the presentation mode. My conclusion is your patch for Fully External Display Mode is partially successful.

Does the toast notification show the correct external display resolution when you launch the stream?
Is the video stream resolution in the performance stats have the same as the external monitor resolution?

i did another test on another monitor. the monitor output is full screen without blank space. i think it is another issue with Android native presentation mode.

the new issue is, mouse movement is not captured with the fix. I think this is gap produced by the Presentation mode either. Trying to fix this now.....

The patch I made is a proof of concept at best. The actual patch should capture the Window upstream in the ServerHelper where the intent is instantiated, rather than capturing the Views inside.

[bynkook]

Also running into the same problem on my Pixel 8 Pro. Seems like Android prefers app developers to utilize the Presentation API over ActivityManager.
https://source.android.com/docs/core/display/multi_display/activity-launch https://developer.android.com/reference/android/app/Presentation
I've verified that creating a Presentation dialog for the external display produces the expected results (external display in mirror mode switches to max resolution and streams the video correctly). f024635

I've tested your patch with my Galaxy 25+. the patch does not produce the error and launched the game mode successfully. One thing not fixed is the mode make blank black space on left and right edges of external monitor output. I will dig more into the presentation mode. My conclusion is your patch for Fully External Display Mode is partially successful.

Does the toast notification show the correct external display resolution when you launch the stream?
Is the video stream resolution in the performance stats have the same as the external monitor resolution?

i did another test on another monitor. the monitor output is full screen without blank space. i think it is another issue with Android native presentation mode.
the new issue is, mouse movement is not captured with the fix. I think this is gap produced by the Presentation mode either. Trying to fix this now.....

The patch I made is a proof of concept at best. The actual patch should capture the Window upstream in the ServerHelper where the intent is instantiated, rather than capturing the Views inside.

successfully implemented your PoC code into my repository. it works real nice. One thing is mouse cursor movement is not working. Only clicking works. Maybe the Presentation mode is supposed to be like this? Any input appreciated.

[ClassicOldSong]

Presentation has syncing issues. It can't force lock refresh rate, can't trigger full screen systemui hiding, so it's removed.

[bynkook]

Presentation has syncing issues. It can't force lock refresh rate, can't trigger full screen systemui hiding, so it's removed.

please enlighten with any good guide to patch the error.

[ClassicOldSong]

I mean presenting itself. Artemis previously has a presentation mode but after full external display mode come out, it's a way better option so that's removed.

[XDleader555]

Would bringing back presentation mode as a compatibility configuration flag be an option? It would seem that setLaunchDisplayId is not an option for non-root users since external displays lack the proper system permission flags.

I was able to run games fine in presentation mode with no noticeable issues or slowdowns.

[ClassicOldSong]

It's a standard Android API and doesn't require root. I don't think Google will block this API as they're implementing multi display support themselves.

[bynkook]

Follow-up from my local test branch (fix-external-display-launch-policy).

Current local change summary:

• ExternalDisplayControlActivity now uses the Game.EXTRA_DISPLAY_ID already stored in the wrapped Game intent, instead of re-selecting a secondary display again.
• startActivity(gameIntent, options.toBundle()) is wrapped in try/catch so a rejected ActivityOptions.setLaunchDisplayId() does not crash or silently stop the session.
• On launch failure, the fallback removes Game.EXTRA_DISPLAY_ID before starting Game normally. This avoids a mixed state where the app falls back to the default display but Game still thinks it should use the external display.
• I removed the experimental createDisplayContext(...).startActivity() fallback attempt. It did not bypass the framework check on my phone and failed with the same launch-display denial.

Relevant local code shape:

try {
    startActivity(gameIntent, options.toBundle());
} catch (RuntimeException e) {
    LimeLog.warning("Failed to launch game on external display: "
            + e.getClass().getSimpleName() + ": " + e.getMessage());
    startDefaultDisplayGame(gameIntent);
    return;
}

private void startDefaultDisplayGame(Intent gameIntent) {
    gameIntent.removeExtra(Game.EXTRA_DISPLAY_ID);
    LimeLog.warning(getString(R.string.no_external_display));
    startActivity(gameIntent);
    finish();
}

Test result on my Galaxy S25+ after the recent firmware update:

• The app no longer crashes when the external-display launch is rejected.
• However, Fully External Display Mode still does not actually work on this phone in Galaxy screen mirroring mode. It falls back to the normal/default display path.
• The external monitor output then looks like normal mirror-mode streaming, including the black margins / non-fullscreen behavior.
• A separate tablet test with the original app does work correctly with Fully External Display Mode, so this does not look like a general Artemis logic failure. It looks device/display-policy specific.

My current guess:

setLaunchDisplayId() is a public Android multi-display Activity launch API and does not require root. The failure on my Galaxy S25+ seems to be that Samsung screen mirroring exposes a non-default external display, but that display is not allowed to host an Activity task for this app after the firmware update. In that case Android rejects the launch with a SecurityException / runtime launch failure.

So the clean fallback patch is useful to avoid crash / silent stop / hybrid state, but it is not a full fix for making this specific phone force-enter real Fully External mode. The remaining root problem appears to be launchability of the external display, not Presentation mode or mouse input.