Why Xiaomi itself is decreasing the brightness of the screen – all the reasons and ways to fix

Why Xiaomi Phones Are Danging Without You

Have you noticed that your Xiaomi screen has become spontaneously dimmed, even though you haven’t touched the brightness regulator? This is a common problem faced by owners of smartphones of the brand — from budget Redmi to flagship Mi or POCO. The reasons can be both software (power saving functions included, adaptive lighting) and hardware (overheating, battery wear or matrix).

In this article, we will discuss all possible causes of automatic brightness decline on Xiaomi, including hidden settings. MIUI, You'll learn how to distinguish between normal system behavior and failure, and you'll also get step-by-step instructions for diagnosing and fixing the problem. AMOLED-screens (for example, Xiaomi 13 Pro or Redmi) K60), where dimming may be due to the features of organic LEDs.

If your phone has become “ghostly” fading when watching videos, in games or with low battery power, read on. We have gathered data from official Xiaomi documentation, user reviews on forums (including 4PDA and Mi Community) and lab tests to provide the most complete picture.

1. Adaptive brightness: how it works and why it “glues”

The most common cause of spontaneous brightness changes is the adaptive lighting function in MIUI, which uses a light sensor to automatically adjust the brightness of the screen depending on the ambient light, which is convenient in theory, but in practice users face a number of problems:

🔄 Unstable sensor performance: If it is contaminated or damaged, the phone may mistakenly “think” that it is dark and mute the screen even during the day.
📱 Conflict with the shell MIUI: After updates, the system sometimes resets the adaptive brightness settings to default values (for example, up to 30-40% of the maximum).
🌡️ Overheating of the sensor: during prolonged operation in hot conditions (for example, in a car under the sun), the sensor can give false readings.

To check if adaptive brightness is to blame, follow the following steps:

Open the settings → Display → Brightness.
Turn off the Adaptive Brightness slider (or Auto Brightness in older versions of MIUI).
Manually set the brightness to a comfortable level and observe the behavior of the screen for 10-15 minutes.

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If after turning off the adaptive brightness, the problem disappeared, but you are not comfortable constantly adjusting the backlight manually, try resetting the sensor settings. To do this, go to Settings → About the phone → All parameters → Reset sensor settings (not available on all models).

On some models (such as the POCO F5 or Redmi Note 12 Pro+), adaptive brightness may conflict with the Vision Protection function (blue light). If the screen dims in the evening, check the schedule of this mode in Settings → Display → Read Mode.

2. Power saving modes: hidden limitations of MIUI

MIUI aggressively optimizes power consumption, and often it affects the brightness of the screen. Even if you haven't manually turned on the power saving mode, the system can activate it automatically when:

🔋 Battery charge below 15-20% (threshold depends on model).
🔥 Overheating of the processor (for example, during games or charging).
📴 Long-term work in the background (for example, if the phone was lying without use for several hours).

To check the impact of energy saving:

Go to Settings → Battery and Performance → Battery Mode.
Select “High Performance” (disables all restrictions).
Check if the problem persists. If so, move on to the next section.

📊 Your Xiaomi phone often overheats?

Yeah, especially in games.

Only when charging.

Rarely.

Never.

⚠️ Note: Some models (e.g. Xiaomi) 12T or Redmi K50) In energy-saving mode, the brightness is limited to 50 percent of the maximum, even if you're manually trying to increase it.

Also worth checking is Super Power Saving, an extreme mode that is activated at a critically low charge (usually <5%), which fixes brightness at a minimum level and blocks background processes, only turning off when connected to charging.

3.Overheating: why the screen dims when loaded

If the brightness drops during gaming, video shooting or heavy use, it is overheating. Xiaomi (like other manufacturers) software limits brightness and performance to protect the battery and chipset from damage. AMOLED-screens that warm up more IPS.

How to diagnose overheating:

🌡️ Use the app. AIDA64 or CPU Monitor to check the temperature of the processor.Critical values: Snapdragon 8 Gen 2 (e.g., Xiaomi 13 Ultra): above 65°C; Dimensity 9000 (e.g. in Redmi) K60 Pro: above 70°C; Snapdragon 778G (for example, POCO X4 Pro: above 55°C.
🔍 Check if the cover is blocking the vents (if any).
🔋 Do you charge your phone while you play? It increases the heat.

Xiaomi model	Typical load temperature	Trottling temperature (brightness limits)
Xiaomi 13 Pro	45–55°C	60°C+
Redmi Note 12 Pro+	40–50°C	55°C+
POCO F4 GT	50–60°C	65°C+
Xiaomi 12 Lite	35–45°C	50°C+

If overheating is confirmed, try:

Limit it. FPS games up to 60 Hz|Remove the case while charging|Use the original power supply unit|Turn off background processes in battery settings|Do not place your phone on soft surfaces (such as a bed)-->

On liquid-cooled models (such as the Black Shark 5 Pro or POCO F5), brightness can decrease even at temperatures of 50-55°C, which is normal as the system tries to conserve the cooling system’s life.

Battery wear: relationship to screen brightness

Few people know, but a degraded battery can indirectly affect the brightness of the screen, and when the battery capacity drops below 70-80% of the original, the power controller starts to limit the power consumption of the display to extend the time.

📉 A sharp decrease in brightness when charged below 30-40%.
🔄 «Twitching" backlighting when connecting / disabling charging.
🛑 Inability to set brightness above 60-70% even manually.

How to check the status of the battery:

Go to Settings → Battery and Performance → Battery Status
Look at the value of "Capacity." If it's below 80%, the battery needs to be replaced.
Use the AccuBattery app for detailed diagnosis.

How to reset the data on the battery zikts?

On some Xiaomi models, you can reset the charging cycle counter via the engineering menu. To do this: Dial in the phone app ##4636##. Select Battery Information. Click Reset Statistics (if available).

If the battery is worn out, it can temporarily help:

🔌 Use battery calibration (discharge to 0%, then charge to 100% without interruptions).
⚡ Disabling fast charging in Settings → Battery → Charging settings.
🔄 Resetting settings to factory (sometimes helps with power controller failures).

⚠️ Attention: On models with AMOLED-screens (e.g. Xiaomi) 11T Pro) a worn-out battery can cause backlight flickering at low brightness, due to unstable voltage applied to the matrix.

5. Firmware failures and MIUI errors

Sometimes the cause of the screen dimming is software errors MIUI, which can manifest after updating, resetting settings or installing custom firmware.

🔄 Brightness “jumps” on its own, even if the adaptive backlight is turned off.
📵 Brightness settings are not saved after restarting.
🛠️ B Settings → The display lacks a slider brightness.

How to diagnose and correct:

Clear the system cache: Go to Settings → Memory → Clean. Select “Clear system cache”.
Reset the display settings: Settings → System → Reset settings → Reset display settings
Reinstall the MIUI Update: Download the latest firmware for your model from the official Mi Community website. Go to Settings → About Phone → System Update → Three Dots (menu) → Select a firmware file.

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If the problem occurred after the MIUI update, try rolling back to the previous version. To do this, download the archive with the firmware, rename it to update.zip and install it through Recovery (press Power + Volume Up when you turn it on).

On forums, users often complain about brightness bugs after upgrades to MIUI 14 and HyperOS. For example, on Xiaomi 12 and Redmi K50 after the update, brightness was fixed by 50%, and only a full reset could help.

6. Hardware malfunctions: when without service can not do

If all software methods have been tried, but the brightness still drops on its own, the problem may be in the hardware.

Malfunction	Symptoms	Possible solution
Damage to the display plume	Brightness 'jumps' when tapping on screen or bending phone	Replacement of the plume (cost: 1,500–3,000) ₽)
Illumination sensor failure	Adaptive brightness does not work, the screen is always dim or too bright.	Replacement of sensor (cost: 800–2,000) ₽)
Degradation AMOLED-matrix	Uneven dimming (one part of the screen is darker than the other)	Replacement of the display (cost: 5,000–15,000) ₽)
Failure of the illumination controller	The screen flickers or completely fades at low brightness	Mainboard repair (cost: 3,000–10,000) ₽)

How to check for hardware problems:

🔦 Light the flashlight on the light sensor (usually located next to the front camera). If the brightness does not change, the sensor is defective.
📱 Lightly press the screen in different places. If the brightness changes, the problem is in the plume or matrix.
🔍 Check the screen for burnt pixels (especially on the screen). AMOLED). Use test images with a uniform color (for example, in the Screen Test application).

⚠️ Note: On Xiaomi models with AMOLED-screens (e.g. Xiaomi 13 or Redmi) K60) The dimming may be due to the production of organic LEDs, which eventually lose their brightness, and it's irredeemable.

If you suspect a hardware malfunction, don't try to repair the phone yourself, which could cause more damage. Contact Xiaomi Service Center or a trusted repair center. The average cost of a diagnosis is 500-1000. ₽.

7 External factors: covers, films and magnets

Sometimes the cause of dimming is external accessories, and this can affect brightness.

🧲 Magnetic cases or mounts: if they are located near the light sensor, can cause false positives. Especially relevant for cases with a smart alarm (for example, Xiaomi Smart Cover).
📱 Darkened protective glass: Some films have a light-absorbing coating, which is why the light sensor “thinks” that it is dark around.
☀️ Direct sunlight: In bright light, the sensor may fail and adjust the backlight incorrectly.

To check the impact of accessories:

Remove the cover and the safety glass.
Wipe the light sensor area with an alcohol napkin.
Check the brightness behavior in different lighting conditions.

If the problem is gone, it's the accessory. Try using cases without magnets or glass with a notch under the sensor.

Frequent Questions (FAQ)

Why does Xiaomi’s brightness decrease when watching videos?

This could be due to: Activation of the movie mode (in some models it automatically reduces brightness to save charge); Adaptive brightness work, which responds to changing lighting in the room; CPU overheating when decoding video (especially in 4K or HDR); Solution: turn off adaptive brightness and check the temperature of the phone during playback.

On Xiaomi, the brightness itself decreases to a minimum and does not increase.

This is a typical symptom: Light sensor failure (replacement needed), hardware failure of the plume or matrix, critical battery wear (capacity below 60%), first try resetting the display settings to Settings → System → Reset. If it doesn't help, contact the service.

After the MIUI update, the screen became dim. How do you get back to its brightness?

The update could: Reset adaptive brightness settings. Activate hidden energy saving mode. Make changes to the color profile (e.g., turn on sRGB instead of Vivid). Solution: Go to Settings → Display → Screen Colors and select Live. Turn off adaptive brightness and set the value manually. Reset the display settings (see section 5).

On Xiaomi AMOLED-One part of the display is dimmer than the other?

No, it's a sign of uneven degradation of the matrix or problems with illumination. AMOLED-In the screens, organic LEDs wear out over time, and if you use your phone at maximum brightness often, some areas may burn out faster. Solution: contact the service for diagnosis. If the degradation is severe, you'll need a replacement display. Cost for Xiaomi 13 Pro or Redmi K60 Pro - 8,000 to 15,000 ₽.

Can automatic brightness decrease be turned off at low charge?

Partially. MIUI doesn't allow you to completely disable this limitation, but you can: Select High Performance mode in the battery settings. Turn off Super Power Saving. Use a custom core (requires root rights). On some models (e.g., POCO F3), it helps to disable the MIUI Optimization function in the developer settings.