rtl8811au on Raspberry Pi4: driver module builds and loads, but no interface device appears

[TheOneWhoseUsernameWasTaken]

Hello!

I'm trying to get a Logilink WL0238 adapter (rtl8811au) to work on a RPi4. I built the module according the instructions, with one seemingly necessary deviation: The instructions say that for the Pi4, I need to to build the ARM64 module. But I'm using the normal 32bit Raspbian (now Pi OS), so I went with the Pi2 sed-command.

I also disabled the built-in wifi by blacklisting brcmfmac and brcmutil. The reason I want to use an USB adapter is that I had reliability issues with those, so I wanted to test a different adapter with a real antenna.

I ran the dkms-install.sh command, it completed without errors, and after a reboot, I could load the module. But no wifi interface device seems to show up. 'iw dev' has no output, the desktop GUI says it can't detect any wifi devices.

What am I doing wrong?

# uname -a
Linux cammon 5.4.51-v7l+ #1333 SMP Mon Aug 10 16:51:40 BST 2020 armv7l GNU/Linux

# cat /etc/debian_version 
10.4

# modprobe 88XXau

# lsmod | grep 88XXau
88XXau               2027520  0
cfg80211              679936  1 88XXau

# dmesg | tail -n4
[   32.537570] cfg80211: Loading compiled-in X.509 certificates for regulatory database
[   32.578954] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
[   32.646534] 88XXau: loading out-of-tree module taints kernel.
[   32.679229] usbcore: registered new interface driver rtl88XXau

# iw dev

# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether dc:a6:32:42:30:ac brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.77/24 brd 192.168.0.255 scope global eth0
       valid_lft forever preferred_lft forever

# cat /proc/net/wireless 
Inter-| sta-|   Quality        |   Discarded packets               | Missed | WE
 face | tus | link level noise |  nwid  crypt   frag  retry   misc | beacon | 22

# ls /sys/class/net/
eth0  lo

# lsusb -D /dev/bus/usb/001/003 
Device: ID 0bda:c811 Realtek Semiconductor Corp. 
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            0 
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0x0bda Realtek Semiconductor Corp.
  idProduct          0xc811 
  bcdDevice            2.00
  iManufacturer           1 Realtek
  iProduct                2 802.11ac NIC
  iSerial                 3 123456
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x0035
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower              500mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           5
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass    255 Vendor Specific Subclass
      bInterfaceProtocol    255 Vendor Specific Protocol
      iInterface              2 802.11ac NIC
      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     0x87  EP 7 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               3
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x08  EP 8 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
Device Qualifier (for other device speed):
  bLength                10
  bDescriptorType         6
  bcdUSB               2.00
  bDeviceClass            0 
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  bNumConfigurations      1
can't get debug descriptor: Resource temporarily unavailable
Device Status:     0x0000
  (Bus Powered)

[ulli-kroll]

Next time you should use/add the USB id in the title.

0bda:c811 is part of the vanilla rtl88cu device driver from Realtek either use https://github.com/ulli-kroll/rtl8821cu or this branch https://github.com/ulli-kroll/rtw88-usb/tree/development/chipset/rtl8822cu

[TheOneWhoseUsernameWasTaken]

Well, the manufacturer's own data sheet states as chipset: "RTL8811AU". And Google then led me here.

None of the drivers you linked to will work for me. First one doesn't even build:

# LC_ALL=C make
make ARCH=armv7l CROSS_COMPILE= -C /lib/modules/5.4.51-v7l+/build M=/root/rtl8821cu  modules
make[1]: Entering directory '/usr/src/linux-headers-5.4.51-v7l+'
Makefile:648: arch/armv7l/Makefile: No such file or directory
make[1]: *** No rule to make target 'arch/armv7l/Makefile'.  Stop.
make[1]: Leaving directory '/usr/src/linux-headers-5.4.51-v7l+'
make: *** [Makefile:480: modules] Error 2

And the second's build process doesn't match the instructions, and the final modules have unknown symbols. See: https://github.com/ulli-kroll/rtw88-usb/issues/10

[satmandu]

@TheOneWhoseUsernameWasTaken If you have a arm7l userland with an arm64 kernel you may have to install the arm64 headers on your rpi4 to get arm64 kernel headers installed.

Use this script to do that: https://gist.github.com/satmandu/a507c59d84737f6d29ff353395819d51

[TheOneWhoseUsernameWasTaken]

Just as a quick update from my end: I couldn't get it to work, and the project deadline was approaching, so I spend another whopping 12 bucks and got myself a different wifi adapter. Now I'm using an Edimax EW-7711UAn V2 (usb id 7392:7710) which seems to use a Mediatek chipset (driver mt7601u). And it just works. Out of the box.

[dash042]

I am actually having this issue with a ALFA AWUS036ACH with Arch Linux... Anyone using Arch?