Hello,

I have just installed Debian Trixie on a Dell Precision 5860 workstation
that initially had Ubuntu on it. The installation went well but there
are two issues. This post is about the second of these.

The system is connected via Ethernet over the power line and this works
well enough. However, I also have a USB WiFi adapter (TP-Link Archer
T3U (Realtek RTL8812BU)) which, when using Ubuntu, provided much better performance. On Debian, I cannot get the system to recognise this
device.

I have done some searching and found two possible drivers for this
adapter:

1. https://github.com/morrownr/88x2bu-20210702.git
2. https://github.com/fastoe/RTL8812BU.git

The first compiles and installs fine but has no effect. The second does
not build (lots of errors during compilation).

I have no idea on how to proceed. This is not mission critical as I do
have a working network connection but it would be nice to have the
better performance.

Suggestions welcome.

Thank you,
eric

--
Eric S Fraga via gnus (Emacs 31.0.50 2026-02-11) on Debian 13.3

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Subject: Re: Installing trixie on Dell Precision 5860: 2. WiFi USB adapter not found

Le 12/02/2026 … 09:22, Eric S Fraga a ‚critÿ:

Hello,

I have just installed Debian Trixie on a Dell Precision 5860 workstation
that initially had Ubuntu on it.

[...]

I also have a USB WiFi adapter (TP-Link Archer
T3U (Realtek RTL8812BU)) which, when using Ubuntu, provided much better performance. On Debian, I cannot get the system to recognise this
device.

I have done some searching and found two possible drivers for this
adapter:

1. https://github.com/morrownr/88x2bu-20210702.git
2. https://github.com/fastoe/RTL8812BU.git

[...]

Hello,

Since linux 6.2, it seems there is no need for an external driver: https://linux-hardware.org/?id=usb:2357-012d

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Subject: Re: Installing trixie on Dell Precision 5860: 2. WiFi USB adapter not found

didier gaumet <didier.gaumet@gmail.com> writes:

Since linux 6.2, it seems there is no need for an external driver: https://linux-hardware.org/?id=usb:2357-012d

Is there a page which says whether that thing needs external firmware or
not? Such that can be found in the firmware-realtek package, for
example?

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Subject: Re: Installing trixie on Dell Precision 5860: 2. WiFi USB adapter not found

Response below/inline for email didier gaumet wrote:

(original email sent 12 Feb 2026 at 09:52)

Since linux 6.2, it seems there is no need for an external driver: https://linux-hardware.org/?id=usb:2357-012d

Interesting and thanks. Any idea why the system doesn't make use of the adaptor then? Is there something I need to do/configure?

eric
--
Eric S Fraga via gnus (Emacs 31.0.50 2026-02-11) on Debian 13.3

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Subject: Re: Installing trixie on Dell Precision 5860: 2. WiFi USB adapter not found

Response below/inline for email Anssi Saari wrote:

(original email sent 12 Feb 2026 at 12:41)

Is there a page which says whether that thing needs external firmware or
not? Such that can be found in the firmware-realtek package, for
example?

Interesting. I do have firmware-realtek installed so decided to

sudo dpkg-reconfigure firmware-realtek

which updated the initramfs (which I believe it did before but just in
case) and now, after rebooting, the NetworkManager applet does show a
WiFi section but says that the device is not managed. This is a step
forward as before there was no WiFi at all.

The nmtui program says that Wi-Fi is enabled both hardware and software
but doesn't let me configure it.

In the system logs, I see:

[ 8.830278] usbcore: registered new interface driver rtw_8822bu
[ 8.834456] rtw_8822bu 2-4:1.0 wlx3c52a1c369c7: renamed from wlan0
[...]
[ 50.869339] rtw_8822bu 2-4:1.0: firmware failed to leave lps state

so the driver is actually found but there seems to be a problem.

I continue to investigate...

Thanks,
eric

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Eric S Fraga via gnus (Emacs 31.0.50 2026-02-11) on Debian 13.3

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Subject: Re: Installing trixie on Dell Precision 5860: 2. WiFi USB adapter not found

Response below/inline for email Eric S Fraga wrote:

(original email sent 12 Feb 2026 at 12:01)

[...]
[ 50.869339] rtw_8822bu 2-4:1.0: firmware failed to leave lps state

so the driver is actually found but there seems to be a problem.

I continue to investigate...

So, having found this page:

https://askubuntu.com/questions/1449227/rtw-8821ce-firmware-failed-to-leave-lps-state

I added a file to the modprobe config as indicated. I also created an
entry in /etc/NetworkManager/conf.d, specifically a file with contents

--8<---------------cut here---------------start------------->8---
[connection]
wifi.powersave = 2
--8<---------------cut here---------------end--------------->8---

and now the driver does not fail. Which of the changes made a
difference is yet to be determined but, in any case, the WiFi interface
is still not "managed" by NM. How do I tell NM to manage the WiFi?

Thanks again,
eric

--
Eric S Fraga via gnus (Emacs 31.0.50 2026-02-11) on Debian 13.3

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Subject: Re: Installing trixie on Dell Precision 5860: 2. WiFi USB adapter not found

Le 12/02/2026 … 12:27, Eric S Fraga a ‚critÿ:

Interesting and thanks. Any idea why the system doesn't make use of the adaptor then? Is there something I need to do/configure?

Do you see your interface with:
sudo iw dev
?

If you see your wireless interface it is manageable by your system at
low level but if your interface is mentioned in /etc/network/interfaces
then NetworkManager (nmcli, nmtui, nm graphic applet, etc...) won't
manage it until this interface is commented in /etc/network/interfaces

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Subject: [SOLVED] Re: Installing trixie on Dell Precision 5860: 2. WiFi USB adapter not found

Response below/inline for email didier gaumet wrote:

(original email sent 12 Feb 2026 at 14:27)

Do you see your interface with:
sudo iw dev

Yes.

If you see your wireless interface it is manageable by your system at
low level but if your interface is mentioned in
/etc/network/interfaces then NetworkManager (nmcli, nmtui, nm graphic
applet, etc...) won't manage it until this interface is commented in /etc/network/interfaces

Ah ha, that's it. I didn't consciously put the information into that
file; it must have been done during the installation of Debian
yesterday.

It's now working perfectly. Many thanks!

Now just have issue 1 remaining (sound via HDMI).

eric
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Eric S Fraga via gnus (Emacs 31.0.50 2026-02-11) on Debian 13.3

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