Linux 7.2 To Support Realtek RTL8159 10GbE USB Ethernet - Phoronix

The Linux 7.2 kernel cycle will bring mainline support for Realtek’s RTL8159 10GbE USB Ethernet controller, a change that simplifies high-speed wired networking setups for Linux users across desktops, laptops, and homelab servers. The code, developed by open-source contributor Birger Koblitz, has been merged into the networking subsystem’s net-next Git branch, locking it in for inclusion in the Linux 7.2 release due this summer, as reported by Phoronix.

Previously, the RTL8159 was only supported by Realtek’s out-of-tree r8152 driver, which required manual installation, DKMS configuration, or custom kernel builds to function. Mainline inclusion means the driver will ship by default in all Linux distributions that adopt kernel 7.2 or newer, removing a common pain point for users adding 10GbE connectivity via USB.

Product Background: Realtek RTL8159 and Compatible Adapters

The RTL8159 is a USB 3.2 Gen 2-compatible Ethernet controller designed to deliver 10Gbit link speeds over a USB interface. It targets compact systems where PCIe 10GbE cards are not an option, including mini PCs, thin laptops, and 1U servers with spare USB 3.2 ports. Several retail adapters already use the chipset, with prices falling below $100 USD, a sharp drop from earlier 10GbE USB options that often retailed for $150 or more.

One of the most widely available RTL8159-based adapters is the XikeStor 10G USB 3.2 Gen 2 adapter, priced at $99 USD on Amazon. The adapter uses a USB-C interface to connect to host systems, drawing power directly from the USB port with no external power supply required for most use cases.

Performance and Firmware Requirements

Testing of the RTL8159 reveals a critical dependency on PHY firmware to reach full 10Gbit speeds. Without the correct firmware loaded, the controller caps at 5Gbit link rates, as noted in Koblitz’s merge request. The mainline r8152 Ethernet driver now includes code to use the existing firmware upload mechanism for RTL8157 and RTL8159 PHYs, with the firmware binary extracted from the out-of-tree Realtek driver’s ram17 u8 array.

The necessary firmware will be submitted separately to the linux-firmware.git repository, but is not yet present in the main branch. Users installing Linux 7.2 immediately after release may need to manually extract and install the PHY firmware to achieve 10Gbit speeds, though the process will become automatic once the firmware is merged to linux-firmware and included in distribution package repositories.

Power consumption figures for the RTL8159 are not yet publicly benchmarked in mainline configurations, but comparable 10GbE USB controllers typically draw 3 to 5 watts under full load, with idle power draw below 1 watt. The RTL8159’s USB 3.2 Gen 2 interface provides sufficient bandwidth for 10GbE Ethernet, as the interface’s 10Gbit/s raw throughput (after encoding) exceeds the 10Gbit Ethernet line rate.

Compatibility and Build Recommendations

Mainline support covers all RTL8159-based adapters, including models from XikeStor, OWC, and other third-party manufacturers using the same controller. The driver is backward compatible with older USB 3.0 ports, though link speeds will be limited to 5Gbit or lower on ports that do not support USB 3.2 Gen 2’s 10Gbit/s transfer rate.

For homelab builders, the RTL8159 fills a gap in budget 10GbE options. Mini PCs like the Intel NUC 13 Pro or AMD Ryzen 7000-series mini ITX boards with spare USB 3.2 ports can gain 10GbE connectivity for under $100, avoiding the $200+ cost of a PCIe 10GbE card and compatible riser. Laptop users who need wired 10GbE for large file transfers or network-attached storage access can also use the adapters, with plug-and-play support once kernel 7.2 is adopted.

Comparison of common 10GbE USB controllers:

Controller	Max Link Speed	Typical Adapter Price	Mainline Linux Support
Realtek RTL8159	10Gbit	$99	Linux 7.2+
Marvell AQC111U	10Gbit	$149	Linux 5.17+
Realtek RTL8156	2.5Gbit	$29	Linux 5.8+

The table above shows the RTL8159 offers 10Gbit speeds at a lower price point than the previously available Marvell AQC111U, with mainline support arriving later but eliminating the need for out-of-tree drivers from day one of kernel 7.2 release.

Users running long-term support distributions like Ubuntu 24.04 LTS or Debian 12 will need to wait for their respective vendors to backport the r8152 driver update, or install a mainline kernel PPA to gain support earlier. For rolling release distributions like Arch Linux or Fedora Rawhide, the driver will arrive shortly after the Linux 7.2 stable release.