Ad-hoc mode not working with Realtek 8822BU on Raspberry Pi

[Keylost]

System Information
Devices: 2× Raspberry Pi (identical models)
WiFi Adapter: USB WiFi dongles based on Realtek 8822BU (identical models)
Kernel version: 6.1.21-v8+
Commit: fe48647496798cac77976e310ee95da000b436c9

Description of the Issue
I am trying to set up a basic ad-hoc network between two Raspberry Pi devices using USB WiFi adapters based on the Realtek 8822BU chipset. Both devices are placed 1 meter apart.
The ad-hoc interface comes up on both devices, but no connection is established between them. Each device reports a different BSSID.

Network Configuration
First Raspberry Pi (/etc/network/interfaces)

auto wlan1
iface wlan1 inet static
    address 192.168.10.1
    netmask 255.255.255.0
    wireless-mode ad-hoc
    wireless-essid MyAdHocNetwork
    wireless-channel 6

Second Raspberry Pi (/etc/network/interfaces)

auto wlan1
iface wlan1 inet static
    address 192.168.10.2
    netmask 255.255.255.0
    wireless-mode ad-hoc
    wireless-essid MyAdHocNetwork
    wireless-channel 6

Observed Behavior

• Interfaces successfully enter ad-hoc mode on both devices.
• No connection is established between the devices.
• iwconfig shows different BSSIDs on each Raspberry Pi.
• Devices do not see each other (no ping), even though they are in range and on the same channel.

I managed to establish a connection using this driver: https://github.com/lwfinger/rtw88
. However, the connection takes a very long time to establish and is unstable (see lwfinger/rtw88#406 ). It’s not usable. With the driver https://github.com/morrownr/88x2bu-20210702
, I wasn’t able to establish a connection at all. The driver https://github.com/cilynx/rtl88x2bu
doesn’t work either.

I can provide driver logs of the required level if needed.

[morrownr]

Hi @Keylost

The README does not show adhoc support. Most modern drivers no longer support adhoc as P2P has pretty much taken over the roll of adhoc.

Therefore, I recommend you look at using P2P. Also, as long as your are using RasPiOS based on Debian 13 with kernel 6.12, you do not need this driver as there is a good in-kernel driver. If you are interested in switching to the new rtw88 standards compliant in-kernel driver, let me know and I will point you to additional information.

[Keylost]

The README does not show adhoc support.

The driver reports IBSS mode support via "iw list", so I assumed it might work.
Supported interface modes:
* IBSS
* managed
* AP
* monitor
* P2P-client
* P2P-GO

Is this mode not supposed to work? My goal is to create a small dynamic mesh-like network based on the ad-hoc/IBSS mode. The P2P mode doesn’t seem very suitable for this task. However, if there’s a way to achieve something similar using P2P, I’d be happy to try it :)

In the README, the "Supported Features" section mentions "Mesh" support, but the mesh mode is not listed among the supported ones. What exactly is meant by “Mesh” here, and is there any way to use it for my purposes?