RealTek r8157 not properly detected by kernel. Uses cdc_ncm module instead #43
Description
OS: Oracle Linux 10
Kernel: 6.12.0-200.74.27.el10uek.x86_64
Problem:
It appears either the kernel supplied r8152 module does not properly identify the r8157 device OR it does not support the device. This causes the network device to run at half duplex and auto negotiation to be off.
FIX:
The fix is to blacklist the cdc_ncm module and make/install the module from RealTek. This restores full operation to the network device, at full duplex, with auto negotiation on. All speeds are advertised.
INFORMATION after installation of Realtek module:
Realtek module version:
version: v2.21.4 (2025/10/28)
license: GPL
description: Realtek RTL8152/RTL8153 Based USB Ethernet Adapters
From lsusb:
Bus 004 Device 002: ID 0bda:8157 Realtek Semiconductor Corp. 5G Ethernet Adapter