Dennis HilkLinux diagnosticsDE

Ethernet & networking

Realtek RTL8125 family

The RTL8125 family is handled by the in-tree r8169 driver in this snapshot. Its 2.5-gigabit family capability must be separated from the speed negotiated with a particular switch.

Editorial source review: Share public profileOpen in the identification tool
On this page
  1. Overview & identity
  2. Driver & binding
  3. Firmware
  4. Read-only diagnostics
  5. Limitations & related issues
  6. References

Overview & identity

The table contains 10ec:8125 and the implementation names several A/B/D-family MAC versions. This pair alone is insufficient to pick one revision-specific firmware file.

Curated identifiers
pci 10ec:8125

A numeric match establishes a candidate family within the reviewed evidence. Marketing names, board variants, subsystem conditions and successful operation remain separate questions.

Driver & binding

r8169 is a valid upstream candidate. A distribution kernel can carry a different subset of this source, and an r8125 vendor module is not proof that the upstream candidate is absent.

  • r8169 — kernel driver/module candidate

Detected, bound, operational: learn the difference

Firmware

Conditional firmware path

The source declares these RTL8125 revision-specific examples and additional variants. Firmware selection follows MAC detection; a PCI pair alone cannot select a file.

Checked examples or filename branches, not a complete installation list:

  • rtl_nic/rtl8125a-3.fw
  • rtl_nic/rtl8125b-2.fw

Inspect firmware packaging on your distribution

Read-only diagnostics

Run one displayed command at a time. Replace uppercase placeholders with the affected device, interface or module from your own output. Commands are never executed here. Read-only output can still contain private identifiers.

Check the PCI function and bound driver

lspci -nnk -s BDF

Replace BDF with the domain:bus:device.function address. Look for [10ec:8125] and Kernel driver in use. r8169 in Kernel modules is only a candidate, not proof of binding.

Identify the network interface driver

ethtool -i INTERFACE

Replace INTERFACE with the real interface name. Driver and bus-info connect this interface to its device. A displayed firmware-version is adapter information; it does not prove a file was loaded. Candidate: r8169.

Compare supported modes with the current link

ethtool INTERFACE

Supported/advertised link modes describe capability or negotiation offers. Speed, Duplex and Link detected describe the current link, not measured throughput. An unsupported query is a limitation of the interface/driver.

Separate PCIe transport from Ethernet speed

sudo lspci -vv -s BDF

Elevated access may be needed. Root can expose the full PCI configuration. If PCIe capabilities exist, compare LnkCap with LnkSta: maximum and negotiated PCIe speed/width are different from Ethernet speed. Legacy PCI or virtual functions may omit these fields.

Inspect initialization and firmware requests

sudo journalctl -k -b --no-pager

Elevated access may be needed. Root reads the current boot kernel journal. Locate this controller/interface and the exact requested filename or Safe Mode message. Module-wide firmware declarations are not proof that every listed file was requested for this device.

Limitations & related issues

The family label does not establish a tested kernel/firmware combination. A 1-gigabit link can be the correct negotiated result on a slower partner rather than a driver failure.

These guides are linked for relevant observations, not as known defects of every device in this family.

Choose a hardware diagnostic workflow · Inspect a log excerpt in Fix Lab

References

Source review records a checked implementation or document, not a reproduced hardware test. Version-specific tables do not establish a minimum kernel or guaranteed operation.