DW-AX1850 very slow wifi after reboot

Aahzymandius · July 17, 2025, 6:51am

I bought the DW-AX1850 a couple months ago and installed the rlt8852au-dkms-git drivers. Everything was working great up until today.

My son rebooted the computer and when it came back up, my wifi speed was unbelievably slow. I was getting up to 200Mbit/s ( using speedtest-cli) and now I can barely reach 10Mbit/s.
I have endeavour installed on my laptop and that is sitting right beside my desktop and it is still getting 200Mbit/s network speeds.

I’ve updated the system, there was a new version of the river available, but that didn’t make a difference.
I’ve tried rebooting the system, I’ve made sure my router isn’t throttling my MAC. I disabled random mac address for wifi in Network Manager.

I’m really not sure what to check next. The dongle works fine if I plug it into my other desktop (also running endeavour), though it’s in another room.

I don’t see any errors in dmesg or journalctl though the device appears to register fine

dmesg | grep rtl8852
4.830857] usbcore: registered new interface driver rtl8852au

here’s my system info

System:
Host: duncan Kernel: 6.12.38-1-lts arch: x86_64 bits: 64
Desktop: KDE Plasma v: 6.4.3 Distro: EndeavourOS
Machine:
Type: Desktop System: ASUS product: N/A v: N/A serial:
Mobo: ASUSTeK model: PRIME B450M-A II v: Rev X.0x
serial: BIOS: American Megatrends v: 4002
date: 02/24/2023
CPU:
Info: 6-core model: AMD Ryzen 5 5500 bits: 64 type: MT MCP cache: L2: 3 MiB
Speed (MHz): avg: 2994 min/max: 400/4267 cores: 1: 2994 2: 2994 3: 2994
4: 2994 5: 2994 6: 2994 7: 2994 8: 2994 9: 2994 10: 2994 11: 2994 12: 2994
Graphics:
Device-1: NVIDIA GA102 [GeForce RTX 3090] driver: nvidia v: 575.64.03
Display: wayland server: X.org v: 1.21.1.18 with: Xwayland v: 24.1.8
compositor: kwin_wayland driver: X: loaded: nvidia unloaded: modesetting
gpu: nvidia,nvidia-nvswitch resolution: 1920x1080~60Hz
API: EGL v: 1.5 drivers: nvidia,swrast
platforms: gbm,wayland,x11,surfaceless,device
API: OpenGL v: 4.6.0 compat-v: 4.5 vendor: nvidia mesa v: 575.64.03
renderer: NVIDIA GeForce RTX 3090/PCIe/SSE2
API: Vulkan v: 1.4.313 drivers: nvidia surfaces: N/A
Info: Tools: api: clinfo, eglinfo, glxinfo, vulkaninfo
de: kscreen-console,kscreen-doctor gpu: nvidia-smi wl: wayland-info
x11: xdpyinfo, xprop, xrandr
Audio:
Device-1: NVIDIA GA102 High Definition Audio driver: snd_hda_intel
Device-2: Advanced Micro Devices [AMD/ATI] Renoir Radeon High Definition
Audio driver: snd_hda_intel
Device-3: Advanced Micro Devices [AMD] Family 17h/19h/1ah HD Audio
driver: snd_hda_intel
API: ALSA v: k6.12.38-1-lts status: kernel-api
Server-1: PipeWire v: 1.4.6 status: active
Network:
Device-1: Realtek RTL8111/8168/8211/8411 PCI Express Gigabit Ethernet
driver: r8169
IF: enp8s0 state: down mac: c8:7f:54:0b07
Device-2: D-Link 802.11ac WLAN Adapter driver: rtl8852au type: USB
IF: wlan0 state: up mac: 0c:0e:76:6e:26:10
Bluetooth:
Device-1: ASUSTek ASUS USB-BT500 driver: btusb type: USB
Report: btmgmt ID: hci0 state: up address: N/A
Drives:
Local Storage: total: 3.58 TiB used: 795.52 GiB (21.7%)
ID-1: /dev/nvme0n1 vendor: Western Digital model: WDS500G2B0C-00PXH0
size: 465.76 GiB
ID-2: /dev/sda vendor: Kingston model: SA400S37960G size: 894.25 GiB
ID-3: /dev/sdb vendor: Mushkin model: MKNSSDE3480GB size: 447.13 GiB
ID-4: /dev/sdc vendor: Western Digital model: WD20EARX-00PASB0
size: 1.82 TiB
Partition:
ID-1: / size: 47.45 GiB used: 21.3 GiB (44.9%) fs: ext4 dev: /dev/nvme0n1p2
ID-2: /home size: 392.92 GiB used: 94.98 GiB (24.2%) fs: ext4
dev: /dev/nvme0n1p3
Swap:
ID-1: swap-1 type: partition size: 16 GiB used: 53.2 MiB (0.3%)
dev: /dev/nvme0n1p1
Sensors:
System Temperatures: cpu: 37.0 C mobo: N/A
Fan Speeds (rpm): N/A
Info:
Memory: total: 32 GiB note: est. available: 31.14 GiB used: 2.76 GiB (8.9%)
Processes: 302 Uptime: 37m Shell: Bash inxi: 3.3.38

and output from lsusb

Bus 003 Device 003: ID 2001:3321 D-Link Corp. 802.11ac WLAN Adapter
Couldn’t open device, some information will be missing
Negotiated speed: High Speed (480Mbps)
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 [unknown]
bDeviceSubClass 0 [unknown]
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x2001 D-Link Corp.
idProduct 0x3321 802.11ac WLAN Adapter
bcdDevice 0.00
iManufacturer 1 Realtek
iProduct 2 802.11ac WLAN Adapter
iSerial 3 00e04c000001
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 0x004a
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xe0
Self Powered
Remote Wakeup
MaxPower 500mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 8
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 255 Vendor Specific Subclass
bInterfaceProtocol 255 Vendor Specific Protocol
iInterface 2
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x84 EP 4 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x05 EP 5 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x06 EP 6 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x07 EP 7 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x09 EP 9 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x0a EP 10 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x0b EP 11 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x0c EP 12 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0

manuel · July 17, 2025, 7:24am

Welcome to the forum!

I don’t have this wifi hw so I’ll just ask some general questions.

Just to make sure, do you have package linux-firmware-realtek installed?
Have you tried the default kernel instead of the LTS kernel?
Does it work any better (or at all) if you uninstall the wifi driver package (and reboot)?

Aahzymandius · July 17, 2025, 1:21pm

Thanks for reply.

Linux-firmware-realtek is installed

pacman -Q linux-firmware-realtek
linux-firmware-realtek 20250708-1

I tried booting up with the default kernel instead of LTS, speed is the same.

I can download the driver package from the D-Link site, but I’m not entirely sure how to install them manually.

Meisich · July 17, 2025, 1:41pm

you need USB 3.x for to get AX. With USB 2.x you only get AC and with that only limited speed.

edit:

make a file called “8852au.conf”. Put this line into it

options 8852au rtw_switch_usb_mode=1

save the file and copy it to “etc/modprobe.d”

then plug the AX1850 into an USB 3.x port

restart

there are much more options you can give this adapter. I had it with my old notebook, but cant access it at the moment cause i am not at place. But i made a thread about here on forum

the original 8852au.conf is no more avail on net, but you can also use a 8852bu.conf and replace all the “8852bu.conf” with “8852au.conf” in this file

github.com/morrownr/rtl8852bu-20240418

8852bu.conf

main

# /etc/modprobe.d/8852bu.conf
#
# Purpose: Allow easy access to specific driver options.
#
# Edit the options line below to change, add or delete options if using
# managed (client) mode. If running AP mode, comment this line by adding
# # to beginning of line to inactivate it and see AP mode line further
# down:
#
options 8852bu rtw_switch_usb_mode=0
#
# Note: To activate USB3 mode, change `rtw_switch_usb_mode=0` above to
# `rtw_switch_usb_mode=1`
#
# Edit the options line below to change, add or delete options if using
# AP (hotspot) mode. Uncomment the line by deleting # to activate it and
# don't forget to add # in front of the above options line to deactivate
# it:
#
#options 8852bu rtw_switch_usb_mode=0 rtw_he_enable=2 rtw_vht_enable=2

This file has been truncated. show original

have fun

Aahzymandius · July 17, 2025, 3:24pm

Well maybe now I have a different problem? or the same problem? Either way. I added the config file and I am certain the dongle is plugged into a 3.x USB slot (I double checked the motherboard manual).

Just for fun, I tried every single one of my USB 3.x slots (I have 6) and they all keep showing up as USB 2.0. Is there another way to force the dongle to use USB 3.x instead of 2.0?

Meisich · July 17, 2025, 3:31pm

could you please post the output of

hwinfo | grep 8852au

manuel · July 17, 2025, 3:54pm

Where do they show up as USB 2.0?

Are their cables correctly connected on the motherboard?

Aahzymandius · July 17, 2025, 3:59pm

These are the onboard USB slots, no matter where I connect my dongle, it registers as USB 2.0, even though the USB slot supports 3.x

Here is the output requested:

hwinfo | grep 8852au
rtl8852au: module = 8852au
rtl8852au: /devices/pci0000:00/0000:00:02.1/0000:02:00.0/usb1/1-1/1-1:1.0
net driver: name = rtl8852au, path = /bus/usb/drivers/rtl8852au
V: rtl8852au
E: DRIVER=rtl8852au
E: ID_NET_DRIVER=rtl8852au
E: ID_USB_DRIVER=rtl8852au
8852au 14503936 0 - Live 0x0000000000000000 (OE)
cfg80211 1384448 1 8852au, Live 0x0000000000000000
Driver: “rtl8852au”
Driver Modules: “8852au”

On another note, things appear to be progressing in the wrong direction, the device is still registering, but it won’t connect to any wifi network now.
I had moved the dongle back to my desktop to check stuff there, and when I brought it back, the wifi no longer works.

The results of my test were also interesting. When I plug this same dongle into my other desktop, it ALSO registers as USB 2.0 (this is expected because that desktop does not support USB 3.0) yet it still has speedtest results of 200Mbit/s.

Meisich · July 17, 2025, 4:04pm

according to hwinfo the driver is not active. There should be a line like “driver status 8852au is active”. Please do

sudo modprobe 8852au

and then post the output of

hwinfo | grep 8852au

and

lsusb

again

well, have to do some other things.
So if you see the line “driver status 8852au is active” in hwinfo and “802.11ax” in lsusb, then you have to make the module/driver load persistend/load at startup of the system. For that just copy the 8852au.conf from the “/etc/modprobe.d” folder also into the “/etc/modules-load.d” folder. This will load the driver at startup. If you want to add more options to the driver, just add the additional options behind the “options 8852au rtw_switch_usb_mode=1” line in the 8852au.conf in the “/etc/modules-load.d” folder.

if interested there is an wiki entry for that “modprobe” in Arch

Aahzymandius · July 17, 2025, 8:22pm

That doesn’t look like it changed anything

hwinfo | grep 8852au
rtl8852au: module = 8852au
rtl8852au: /devices/pci0000:00/0000:00:02.1/0000:02:00.0/usb1/1-1/1-1:1.0
net driver: name = rtl8852au, path = /bus/usb/drivers/rtl8852au
V: rtl8852au
E: DRIVER=rtl8852au
E: ID_NET_DRIVER=rtl8852au
E: ID_USB_DRIVER=rtl8852au
8852au 14503936 0 - Live 0x0000000000000000 (OE)
cfg80211 1384448 1 8852au, Live 0x0000000000000000
Driver: “rtl8852au”
Driver Modules: “8852au”

lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 046d:c52b Logitech, Inc. Unifying Receiver
Bus 001 Device 004: ID 0b05:190e ASUSTek Computer, Inc. ASUS USB-BT500ÿ
Bus 001 Device 008: ID 2001:3321 D-Link Corp. 802.11ac WLAN Adapter
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 002: ID 28de:1102 Valve Software Wired Controller
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 005 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 006 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub

cat /etc/modprobe.d/8852au.conf
options 8852au rtw_switch_usb_mode=1

At this point I’m starting to think I’ll just run a cable across the house and leave wifi to the phones

Meisich · July 23, 2025, 4:08pm

Hey! The forum is up again!

Here is a picture how it has to look with hwinfo. As you can see there are some more lines after “driver modules”

But

this realtek usb wifi comes with two different chipsets. Maybe it is the 8852BU and not the 8852AU. So lets try to install the 8852BU for to see if it fits

yay -S 8852bu-dkms-git

Bitterblue · August 26, 2025, 3:51pm

Perhaps your son did more than just reboot the computer.

You can try to delete the connection in System Settings / Wi-Fi & Internet / Wi-Fi & Networking. It will forget the wifi password and any other configuration.