.\"
.\" Copyright (c) 2025 Adrian Chadd <adrian@FreeBSD.org>
.\"
.\" SPDX-License-Identifier: BSD-2-Clause
.\"
.Dd April 5, 2026
.Dt RGE 4
.Os
.Sh NAME
.Nm rge
.Nd RealTek RTL8125/RTL8126/RTL8127/Killer E3000 PCIe Ethernet adapter driver
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following lines in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device rge"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
if_rge_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
driver provides support for various NICs based on the RealTek RTL8125,
RTL8126 and RTL8127 PCIe Ethernet controllers.
.Pp
All of the NICs supported by this driver support 10, 100 and 1000Mbit
over CAT5 cable.
NICs based on the RTL8125 additionally support 2.5Gbit over CAT6 cable.
NICs based on the RTL8126 additionally support 2.5Gbit and 5Gbit over CAT6
cable.
NICs based on the RTL8127 additionally support 2.5Gbit, 5Gbit and 10Gbit
over CAT6 cable.
.Pp
All NICs supported by the
.Nm
driver have TCP/IP checksum offload, hardware VLAN tagging/insertion
features, Wake On Lan (WOL), and use a descriptor-based DMA mechanism.
They are also
capable of TCP large send (TCP segmentation offload).
.Pp
The RTL8125, RTL8126 and RTL8127 devices are single-chip solutions combining
both a MAC and PHY.
The
.Nm
driver manages the PHY directly rather than using the
.Xr miibus 4
interface.
Standalone cards are available in 1x PCIe models.
.Pp
The RTL8125, RTL8126 and RTL8127 also support jumbo frames, which can be
configured via the interface MTU setting.
The MTU is limited to 9126.
Selecting an MTU larger than 1500 bytes with the
.Xr ifconfig 8
utility configures the adapter to receive and transmit jumbo frames.
.Pp
The
.Nm
driver supports the following media types:
.Bl -tag -width "10baseT/UTP"
.It Cm autoselect
Enable autoselection of the media type and options.
The user can manually override
the autoselected mode by adding media options to
.Xr rc.conf 5 .
.It Cm 10baseT/UTP
Set 10Mbps operation.
The
.Xr ifconfig 8
.Cm mediaopt
option can also be used to select either
.Cm full-duplex
or
.Cm half-duplex
modes.
.It Cm 100baseTX
Set 100Mbps (Fast Ethernet) operation.
The
.Xr ifconfig 8
.Cm mediaopt
option can also be used to select either
.Cm full-duplex
or
.Cm half-duplex
modes.
.It Cm 1000baseT
Set 1000baseT operation over twisted pair.
The RealTek gigE chips support 1000Mbps in
.Cm full-duplex
mode only.
.It Cm 2500Base-T
Set 2500Base-T operation over twisted pair.
The RealTek devices support 2.5Gbit in
.Cm full-duplex
mode only.
.It Cm 5000Base-T
Set 5000Base-T operation over twisted pair.
The RealTek devices support 5Gbit in
.Cm full-duplex
mode only.
.It Cm 10Gbase-T
Set 10Gbase-T operation over twisted pair.
The RealTek devices support 10Gbit in
.Cm full-duplex
mode only.
.El
.Pp
The
.Nm
driver supports the following media options:
.Bl -tag -width "full-duplex"
.It Cm full-duplex
Force full duplex operation.
.It Cm half-duplex
Force half duplex operation.
.El
.Pp
For more information on configuring this device, see
.Xr ifconfig 8 .
.Sh HARDWARE
The
.Nm
driver supports the following PCIe Ethernet adapters:
.Pp
.Bl -bullet -compact
.It
RealTek RTL8125 (up to 2.5 Gbps)
.It
RealTek RTL8126 (up to 5 Gbps)
.It
RealTek RTL8127 (up to 10 Gbps)
.It
Killer E3000 (up to 2.5 Gbps)
.El
.Sh SYSCTL VARIABLES
The following variables are available as both
.Xr sysctl 8
variables and
.Xr loader 8
tunables:
.Bl -tag -width "xxxxxx"
.It Va dev.rge.%d.debug
Configure runtime debug output.  This is a 32 bit bitmask.
.It Va dev.rge.%d.rx_process_limit
Maximum number of RX packets to process per interrupt.
The default value is 16.
Increasing this value may improve throughput on high-speed links at the
cost of increased interrupt latency.
.It Va dev.rge.%d.disable_aspm
Disable PCIe Active State Power Management (ASPM) and Extended
Configuration Power Management (ECPM).
The default value is 0 (leave ASPM enabled).
Setting this to 1 reduces latency at the cost of increased power
consumption.
This tunable can only be set in
.Xr loader.conf 5
and requires a reboot to take effect.
.El
.Sh DIAGNOSTICS
.Bl -diag
.It "rge%d: watchdog timeout"
The device has stopped responding to the network, or there is a problem with
the network connection (cable).
.El
.Sh SEE ALSO
.Xr altq 4 ,
.Xr arp 4 ,
.Xr miibus 4 ,
.Xr netintro 4 ,
.Xr ng_ether 4 ,
.Xr polling 4 ,
.Xr re 4 ,
.Xr vlan 4 ,
.Xr ifconfig 8
.Rs
.%U https://www.realtek.com/
.Re
.Sh HISTORY
The
.Nm
device driver first appeared in
.Fx 16.0 .
.Sh AUTHORS
The
.Nm
driver was written by
.An Kevin Lo Aq Mt kevlo@openbsd.org
and ported to FreeBSD by
.An Adrian Chadd Aq Mt adrian@freebsd.org .