[Android USB tethering disconnecting automatically every 10 minutes: Power state fix]

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Root Cause Diagnosis

Android USB tethering automatically drops on a fixed interval when the host operating system’s USB Selective Suspend or Linux autosuspend power management policies put the USB hub into a low-power sleep state. Simultaneously, Android’s internal Doze mode and vendor-specific battery optimization services (e.g., Samsung Device Care, Xiaomi MIUI/HyperOS Battery Saver) classify the active tethering daemon (ipacm or rndis) as an idle background process when the phone screen turns off. This dual-sided power saving forces the USB data interface to reset, tearing down the RNDIS/NCM virtual network adapter every 10 minutes.

Quick Fix

Disable USB autosuspend on the host OS via shell command and prevent Android ADB power management from suspending the USB interface:

  • On Linux Host: “`bash echo -1 | sudo tee /sys/module/usbcore/parameters/autosuspend


* **On Windows Host (PowerShell as Admin):**
```powershell
Get-NetAdapter -Physical | Where-Object {$_.InterfaceDescription -like "*NDIS*" -or $_.InterfaceDescription -like "*RNDIS*"} | Disable-NetAdapterPowerManagement
  • On Android Device (via ADB): “`bash adb shell settings put global stay_on_while_plugged_in 3



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### Step-by-Step Resolution

#### 1. Disable Host USB Selective Suspend (Windows / Linux)

* **Windows OS Configuration:**
1. Open **Device Manager** (`devmgmt.msc`).
2. Expand **Network adapters**, right-click your Android RNDIS/NCM device, and select **Properties**.
3. Navigate to the **Power Management** tab and uncheck **Allow the computer to turn off this device to save power**.
4. Expand **Universal Serial Bus controllers**, open **USB Root Hub** properties, and uncheck the same setting.
5. Open **Power Options** (`powercfg.cpl`) > **Change plan settings** > **Change advanced power settings** > **USB settings** > **USB selective suspend setting** and set it to **Disabled**.


* **Linux OS Configuration:**
Make USB autosuspend permanently disabled for Android devices by creating a Udev rule:
```bash
sudo nano /etc/udev/rules.d/50-android-usb-power.rules

Add the following rule line:

ACTION=="add", SUBSYSTEM=="usb", ATTR{idVendor}=="18d1", ATTR{power/control}="on"

Reload Udev rules:

sudo udevadm control --reload-rules && sudo udevadm trigger

2. Exclude Android Tethering System Services from Battery Optimization

  1. Open Android Settings > Apps > Special app access > Battery optimization (or Unrestricted battery usage).
  2. Switch filter to All apps.
  3. Locate Tethering (or com.android.providers.telephony / TetheringAutomation) and set to Unrestricted / Don’t optimize.
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3. Enable Developer Options for Persistent USB State

  1. Go to Settings > About Phone and tap Build Number 7 times.
  2. Open Settings > System > Developer options.
  3. Enable Keep screen awake while charging (Stay Awake).
  4. Set Default USB configuration to USB tethering.
  5. Enable Mobile data always active (prevents Android from cycling network interfaces when Wi-Fi/cellular state shifts).

Why This Fails for Some Users

  • USB Port Hardware Power Delivery Caps: Type-A ports on older motherboards or unpowered USB hubs often drop voltage when the Android battery reaches 100% and switches from fast charge to trickle charge. The sudden voltage draw shift causes the host USB controller to cycle the port to reset current limits.
  • Aggressive Vendor RAM Managers: Custom Android ROMs (such as Xiaomi HyperOS, OnePlus OxygenOS, or Huawei EMUI) run kernel-level task killers (lmkd tweaks) that ignore standard Android battery optimization whitelist flags, terminating the tethering process when the screen locks for more than 10 minutes.
  • Carrier APN Tethering Timer Limits: Mobile network operators enforce hard IP lease timeouts on secondary APNs (dun APN type). If carrier networks detect a static tethering TTL payload without active TCP keep-alive signals, the carrier gateway drops the data tunnel remotely at strict 10-minute intervals.
  • Faulty USB 3.0/3.1 Controller Drivers: Certain ASMedia or Realtek USB 3.0 host controllers on desktop motherboards exhibit xHCI handoff failures during prolonged steady-state data transfers. Dropping the connection down to a physical USB 2.0 port or using a USB 2.0 cable forces fallback to EHCI drivers, bypassing xHCI link power management (LPM) glitches.

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