The situation when during a phone conversation the display of the smartphone remains on, is familiar to many owners of devices Xiaomi, Redmi and Poco. Instead of going out and locking when you bring the device to the ear, the screen continues to glow, which often leads to accidental tapping of the cheek or ear. This is not only annoying, but can cause a reset of the call or turn on the speaker at the most inopportune moment.
The main reason for this behavior is that the proximity sensor, which is located at the top of the front panel, is not working properly, and in modern models without frames, this sensor is often hidden under the display, making it more sensitive to software failures or contamination. Understanding how this component works is the first step to fixing a malfunction.
In this article, we will discuss in detail all possible reasons why the screen does not go out and propose effective methods for solving the problem. We will consider both the software settings of the MIUI or HyperOS shell, and hardware aspects that can affect the stability of the sensor.
The principle of the sensor approach in smartphones Xiaomi
The proximity sensor is a small infrared module that emits an invisible beam and reads its reflection, and when you hold the phone to your face, the beam bounces off your cheek, and the sensor sends a signal to the system to lock the screen, and if this process is disrupted, the screen remains active.
Xiaomi devices use two main types of sensors: classic, notched speakers, and virtual sensors built directly into the display matrix. Virtual sensors such as the Light Proximity Sensor require software calibration because they do not physically have direct contact with the external environment.
Failures can occur due to the desynchronization of software drivers with the hardware. The operating system may simply “not see” the object in front of the screen due to a software error, ignoring the physical obstacle, and also an important role is played by a protective glass or film, which can block infrared radiation.
- 📱 Classic sensors require a clean hole in the speaker for proper operation.
- 💡 Virtual sensors are sensitive to the thickness and quality of protective glass.
- ⚙️ Device drivers may conflict with Android system updates.
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Use only high-quality protective glass with cutouts for sensors or a transparent area at the top of the screen, so as not to disrupt the work of the sensors.
Software failures and operating system errors
One of the most common reasons why the screen doesn’t turn off when talking to Xiaomi is temporary software failures. Android’s MIUI-coated operating system is a complex software suite where background processes can conflict with each other. Sometimes the process responsible for phone calls just freezes and doesn’t receive a signal from the sensor.
The first thing to do when a problem is detected is to reboot the device completely, which clears RAM and restarts all system services, including telephony services, often after a simple reboot, the problem disappears by itself unless it is caused by physical damage.
Also worth noting is the recent updates: If the problem occurred immediately after the firmware update, it is possible that the new version of the OS contains bugs that have not yet been fixed by the developers, in which case waiting for a patch or a rollback to the previous version of the system helps.
⚠️ Warning: If the screen stopped fading immediately after the firmware update, don't rush to reset.Wait a few days - often Xiaomi releases hot fixes for critical errors within a week of release.
Another factor could be third-party applications intercepting call management: Various number detectors, conversation records, or smart dial interfaces can block the standard screen lock mechanism.
How to check which application is blocking the sensor?
Sensitivity setting and sensor calibration
If the software restart didn’t work, you need to switch to manual tuning and calibration. Xiaomi smartphones have a hidden engineering menu that allows you to test and customize the work of hardware components, accessed through a standard dialing interface.
To enter the engineering menu, dial ##6484##. In the CIT (Customer Integration Test) menu, find the option “Proximity Sensor” or “Proximation Sensor” and you can see the current sensor readings in real time.
If you close the top of the screen with your hand, if the values change (usually from 5.0 to 0.0 or vice versa, depending on the model), then the sensor is physically working. If the numbers don't change, you may need to calibrate. Press the Calibration button and follow the instructions on the screen, closing and opening the sensor in turn.
☑️ Calibration of the proximity sensor
Some versions of HyperOS or MIUI have the option to “Increase Sensitivity” in the basic settings. Go to Settings → About Phone → All Options → Version of the kernel (the path may differ) or look for the sensor-related item in the screen settings. Turning on this option causes the system to respond to less signal reflection.
| Parameter | Normal value. | Value in case of malfunction | Action. |
|---|---|---|---|
| Distance (Distance) | 0.0 - 5.0 cm | Continuous importance | Sizing |
| Raw Data | Changes at closing | It doesn't change. | Pollution checks |
| Status | Near / Far | Only Far. | Resetting settings |
| Light Sensor | Reacts to light. | Zero readings. | Driver verification |
Effects of accessories and physical pollution
Physical obstructions are a trivial but very common reason why the screen doesn't dim when talking: Dust, greasy finger marks, or glue residues from the previous glass can completely block the infrared sensor, especially for models with a sensor under the screen.
Low-quality security glass and film often have an opaque black bezel or just a thick layer of glue at the top. If this zone doesn't match the location of the sensor on Xiaomi, the screen will think that the phone is in your pocket, or vice versa, will not see the approach. In some cases, it helps to remove the case, which can hang over the top edge.
Use a soft microfiber and a special screen tool to clean the oleophobic coating. Don't use aggressive chemicals that can damage the oleophobic coating. Pay special attention to the narrow strip above the display, where the speaker is usually located.
If you've recently changed the security glass, try to remove it carefully and check the phone without it. Often the problem is that the accessory is incompatible with a particular smartphone model. Accessories manufacturers do not always take into account the exact location of the sensors in new models.
Specific features of MIUI and HyperOS
MIUI and HyperOS shells have many features that can conflict with standard screen behavior, such as Pocket Mode, which is designed to prevent accidental taps, but sometimes it works incorrectly by blocking the proximity sensor during a call.
Try disabling this feature in your phone settings. The path to it is usually in Settings → Lock and Protection → Mode in your pocket. Disabling this option can solve the problem, although it will deprive you of protection from pressing in your pocket.
It’s also worth checking the theme settings. Third-party themes downloaded from Themes store may contain errors in the call interface code. If you’ve recently changed the theme, return the standard Classic or Unlimited theme and check the screen.
⚠️ Warning: Third-party themes are a common cause of interface bugs. If the screen stops going out after installing a new theme, return the standard theme first. MIUI.
Another important aspect is the lift-to-response function or gesture control, which uses the same sensors (accelerometer and proximity sensor) and can create a priority conflict, and turning off unnecessary gestures in the special feature menu sometimes helps stabilize calls.
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Disabling the function “Mode in pocket” and returning to the standard theme of design solves the problem in 60% of software cases.
Hardware malfunctions and repairs
If neither calibration, resetting, or cleaning helped, there's a high probability of hardware failure, and the proximity sensor is a physical component that can fail due to a fall, moisture, or factory defect, and in such cases, software methods are powerless.
Signs of hardware failure include a constant sensor response (the screen always dims or never dims) regardless of the position of the hands, and an inability to calibrate in the engineering menu, in which case a replacement of the plume or sensor module is required.
In modern Xiaomi smartphones, the sensor is often soldered into the display plume or the charging port plume (depending on the model). Replacement may require disassembling the device and the presence of special equipment. Self-repair is not recommended, as you can damage the display or break the tightness of the case.
- 🔧 Replacement of the proximity sensor plume (separate module).
- 📱 Replacement of the top plume with the speaker (where the sensor is located).
- 💧 Recovery after moisture (cleaning the board with ultrasound).
If the phone is warranty-free, the repair will be free, and remember that self-opening the case automatically removes the device from warranty service.