Hardware I got a few questions regarding Auto-Brightness

[Diego Liberal]

Hello everyone, I got some questions regarding this function because I'm quite confused about it.
But before asking then away, I need to inform some details first. I got a few 3DS devices and for my questions, information about them will be needed.
Also I would like to point that I tried look it up for answers myself on the internet before posting here.

Devices:

• Old 3DS XL - Upper and lower screens are TN -- Auto-brightness option is NOT available
• New 3DS XL - Upper screen is IPS, lower is TN -- Auto-brightness option IS available
• New 2DS XL - Non hacked, no idea what upper or lower screen are -- Auto-brightness option is NOT available
• New 2DS LL (Dragon Quest edition) - Upper and lower screens are TN -- Auto-brightness option is NOT available HOWEVER, 3DSident states auto-brightness IS available and enabled.

This last one, got region changed before I bought it; it went from Japanese to USA.

All devices are at the latest system version (11.17.0-50U)

1st Question: What is needed to make this option (auto-brightness) available?

From what I gathered from my devices, the screen being TN or IPS is not a factor.
A while back, I was having issues on my OLD 3DS XL screen dimming, in some areas, while playing Shantae and the Pirate's Curse, areas with strong color brightness. I searched online about it and eventually I found the culprit, Energy Saving mode enabled. By disabling it, the screen dimming stopped, as if this was doing the auto-brightness work. I found same behavior at my New 2DS XL and this only happens at my New 3DS XL (the one with IPS screen) if I enable auto-brightness and not Energy Saving.

2nd Question: Is Energy Saving mode equal to Auto-brightness? if so, why there's both as separated options at my New 3DS XL (the one with IPS screen)?

Personally, I don't think they do the same thing, but I could be wrong due what happened with my OLD 3DS XL and New 2DS XL.
Maybe Energy Saving in some conditions attempts to emulate an auto-brightness?

3rd Question: Since 3DSident states the option is available and enabled at my region changed 3DS, could the region change broken the UI making this option unavailable?

This last one is what's bothering me most, but so far, I haven't noticed in any game the brightness changing automatically despite the whole situation with this device in specific.
Also, i don't have the NAND backup from this Japanese device, I'm trying to reach the seller to see if he still has it to revert it back to stock.
Not sure if this is needed but: 3DSident detects correctly that the original system version was Japanese.

 

[Hayato213]

Not sure, but by default you should have auto brightness feature, I got a dual TN one and it has the option.

 

[lisko]

I have a New 3DS xl with both TN screens and obviously auto brightness is available as it's a publicized device function. The difference I notice it's that the Energy saving option apply a fixed constant reduced backlight while auto brightness apply a variable dimming depending on the environmental conditions. Infact I have this option disabled because often happens that near windows it dims the backlight because I slightly orientate the 3DS towards the window while gaming and outside is brighter than inside. I think that the front-facing camera it's what is used to control the actual environmental lighting condition and that it's exclusive to the new 3ds' because the software uses the dedicated cpu core of the super-stable 3d to continuously check the actual environmental lighting condition.

 

[Diego Liberal]

I have a New 3DS xl with both TN screens and obviously auto brightness is available as it's a publicized device function. The difference I notice it's that the Energy saving option apply a fixed constant reduced backlight while auto brightness apply a variable dimming depending on the environmental conditions. Infact I have this option disabled because often happens that near windows it dims the backlight because I slightly orientate the 3DS towards the window while gaming and outside is brighter than inside. I think that the front-facing camera it's what is used to control the actual environmental lighting condition and that it's exclusive to the new 3ds' because the software uses the dedicated cpu core of the super-stable 3d to continuously check the actual environmental lighting condition.

Yeah, Energy Saving indeed changes the brightness and colors to a more dull palette. But from what I seen at my Old 3DS, it wasn't just that, it was indeed dimming the brightness in some parts and rising the brightness in others, despite the function not being available to me on it. (I can reproduce that if anyone wishes to check it out)

But you know what just occurred to me, Nintendo has this page (LINK) that talks about screen brightness, in no where it states that New 2DS XL has the auto-brightness option (Step 3). Still, it would be strange that 3DSident identifying that this option exists on my Japanese one. I may need to unlock my other 2DS XL to double check.

Oh well, from the link I mentioned above, I understood the following:
The following devices doesn't have auto-brightness:

• Old 3DS
• Old 3DS XL
• Old 2DS
• New 2DS XL

The following devices has it:

• New 3DS
• New 3DS XL

Still, they don't explicit mention the New 2DS XL.