illuminance sensor initialization fixes.

[GavinDarkglider]

Please see bug here, patch is supplied, and has been tested on this branch in lakka. mgba-emu#3786

[endrift]

The core issue appears to be that the calls that initialize these values don't have consistent output. That smells like a RetroArch bug that only mGBA hits since it's the only core that I know of that uses the illuminance sensor. This patch is a lot of fluff + one tiny bit of code that make it retry every frame if it can't get the illuminance sensor. This means on platforms that don't have an illuminance sensor (most of them), it will try to reinitialize the sensors every time the game queries the illuminance (or the gyroscope!). That's not ideal, though it might not be the worst.

[endrift]

Can you test this patch instead?

diff --git a/src/platform/libretro/libretro.c b/src/platform/libretro/libretro.c
index 065a9ec4c..12e79131c 100644
--- a/src/platform/libretro/libretro.c
+++ b/src/platform/libretro/libretro.c
@@ -487,6 +487,10 @@ void retro_init(void) {
	lux.readLuminance = _readLux;
	lux.sample = _updateLux;
	_updateLux(&lux);
+	if (luxSensorUsed && !luxSensorEnabled) {
+		// No illuminance sensor was found during startup, but it might finish setup before the first frame
+		sensorsInitDone = false;
+	}
 
	struct retro_log_callback log;
	if (environCallback(RETRO_ENVIRONMENT_GET_LOG_INTERFACE, &log)) {

[GavinDarkglider]

Your patch is much nicer and seems to be working. I have been playing with Claude, trying to fix issues in projects I know nothing about, hince why I didn't submit it as a pr, and supplied a patch in issue thread. Figure if I am going to submit issues, might as well supply potential fixes that lead to better fixes like the one above.

[endrift]

I'll apply it then. Even if I think this qualifies as a RetroArch bug, this version is a harmless workaround.

[GavinDarkglider]

I'll apply it then. Even if I think this qualifies as a RetroArch bug, this version is a harmless workaround.

Well, there was also a bug on the retroach side, but I pushed a fix for that months ago. Lol. Simple returning wrong on failed to open issue. But that is besides the point. Lol.