.\"
.\" Copyright (c) 2022-2026 Bjoern A. Zeeb
.\" Copyright (c) 2026 The FreeBSD Foundation
.\"
.\" Portions of this documentation were written by Bj\xc3\xb6rn Zeeb
.\" under sponsorship from the FreeBSD Foundation.
.\"
.\" SPDX-License-Identifier: BSD-2-Clause
.\"
.Dd May 15, 2026
.Dt RTW88 4
.Os
.Sh NAME
.Nm rtw88
.Nd Realtek IEEE 802.11n/ac wireless network driver
.Sh SYNOPSIS
The driver will auto-load without any user interaction using
.Xr devmatch 8
if enabled in
.Xr rc.conf 5 .
.Pp
Only if auto-loading is explicitly disabled, place the following
lines in
.Xr rc.conf 5
to manually load the driver as a module at boot time:
.Bd -literal -offset indent
kld_list="${kld_list} if_rtw88"
.Ed
.Pp
It is not possible to load the driver from
.Xr loader 8 .
.Sh DESCRIPTION
The
.Nm
driver is derived from Realtek's Linux rtw88 driver based on Linux version 7.0.
.Pp
This driver requires firmware to be loaded before it will work.
The package
.Pa wifi-firmware-rtw88-kmod
from the
.Pa ports/net/wifi-firmware-rtw88-kmod
port needs to be installed before the driver is loaded.
Otherwise no
.Xr wlan 4
interface can be created using
.Xr ifconfig 8 .
One can use
.Xr fwget 8
to install the correct firmware package.
.Pp
The driver uses the
.Xr linuxkpi_wlan 4
and
.Xr linuxkpi 4
compat framework to bridge between the Linux and
native
.Fx
driver code as well as to the native
.Xr net80211 4
wireless stack.
.Sh HARDWARE
The
.Nm
driver supports PCIe devices with the following chipsets:
.Pp
.Bl -bullet -offset indent -compact
.It
Realtek 802.11n  wireless 8723de (RTL8723DE)
.It
Realtek 802.11ac wireless 8814ae (RTL8814AE)
.It
Realtek 802.11ac wireless 8821ce (RTL8821CE)
.It
Realtek 802.11ac wireless 8822be (RTL8822BE)
.It
Realtek 802.11ac wireless 8822ce (RTL8822CE)
.El
.Sh LOADER TUNABLES
.Bl -tag -width indent
.It Va compat.linuxkpi.skb.mem_limit
If you are running a 64bit system with more than 4GB of main memory
you need to set this tunable to
.Sy 1
in
.Xr loader.conf 5
and reboot once to make it effective.
This tunable will work around a problem with DMA and limit allocations
for network buffer memory to the lower 32bit of physical memory and
make the driver work.
.El
.Sh SEE ALSO
.Xr linuxkpi 4 ,
.Xr linuxkpi_wlan 4 ,
.Xr wlan 4 ,
.Xr networking 7 ,
.Xr fwget 8 ,
.Xr ifconfig 8 ,
.Xr wpa_supplicant 8
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 13.2 .
.Sh BUGS
Does not seem to work (reliably) on machines with more than 4GB of
main memory.
See in the
.Sx LOADER TUNABLES
section above.
.Pp
At least the 8821CE and 8822BE chipsets have trouble associating,
which seems to be due to the software scan fallback, the chandef emulation,
and net80211 interactions, along with a 6s timeout observed in the driver.
.Pp
While
.Nm
supports 802.11a/b/g/n/ac modes,
the compatibility code currently only supports 802.11a/b/g modes.
Support for 802.11n/ac is yet to come.