AP Mode Crashing: Raspberry Pi 3B w/two Alfa AWUS036ACM/MT7612U Wireless USB Adapters, OpenWrt 21.02

I'm running a factory image of OpenWrt v21.02 on a Raspberry Pi 3B v1.2 with two Alfa AWUS036ACM USB network adapters (MediaTek 7612U chipset), both at 5GHZ; one in AP mode (lan) and one in Client mode (wwan).

The issue is that the adapter in AP mode crashes within a few seconds of having any load applied to it (~70Mbps+) although if it's running ~50Mbps or less the adapter doesn't crash. After significant research it looks like other users are experiencing the same issue in other flavors of linux. (https://github.com/morrownr/7612u/issues/5).

I replaced one of the AWUS036ACM adapters with a Wireless-N only AWUS036NH (RaLink 3070 chipest) and the issue disappears, but the AWUS036NH adapter is much slower and only able to achieve ~50Mbps which does not meet my project needs (two wireless AC USB adapters/AC speeds). It also has a secondary USB Gigabit Ethernet adapter (wan) that has the Realtek rtl8153 chipset and I use it for wan and troubleshooting when the AWUS036ACM AP adapter crashes and I can no longer connect. It's essentially a Routed AP with an eth1/wan failover.

It works fine as long as both USB adapters aren't the same MicroTek chipset?

I've done a lot of troubleshooting with this and am reaching out to the community for some assistance. Below is the syslog errors and other relevant info. It's looking to me more and more like the issue is the MT7612U driver/firmware and I'm hoping that a few beers and some well earned accolades will be enough to persuade a driver dev to help fix it. These are very popular adapters in the community, it would be nice if two of them played well together.

                          
              (a long list of about 25 of these)
               mt76x2u 1-1.2:1.0: tx urb failed: -71
	           mt76x2u 1-1.2:1.0: tx urb failed: -71
[  751.935327] mt76x2u 1-1.2:1.0: tx urb failed: -71
[  752.386735] usb 1-1.2: USB disconnect, device number 4
[  752.396203] mt76x2u 1-1.2:1.0: mac specific condition occurred
[  752.398543] WARN::dwc_otg_hcd_urb_dequeue:639: Timed out waiting for FSM NP transfer to complete on 6
[  752.423513] wlan0: deauthenticating from 70:4d:7b:11:47:ec by local choice (Reason: 3=DEAUTH_LEAVING)
[  752.651667] mt76x2u 1-1.2:1.0: mac specific condition occurred
[  752.765142] mt76x2u 1-1.2:1.0: mac specific condition occurred
[  752.869117] mt76x2u 1-1.2:1.0: mac specific condition occurred
[  752.869152] mt76x2u 1-1.2:1.0: timed out waiting for pending tx
[  753.193122] usb 1-1.2: new high-speed USB device number 8 using dwc_otg
[  753.302452] usb 1-1.2: New USB device found, idVendor=0e8d, idProduct=7612, bcdDevice= 1.00
[  753.316169] usb 1-1.2: New USB device strings: Mfr=2, Product=3, SerialNumber=4
[  753.328718] usb 1-1.2: Product: Wireless
[  753.337930] usb 1-1.2: Manufacturer: MediaTek Inc.
[  753.347862] usb 1-1.2: SerialNumber: 000000000
[  753.437170] usb 1-1.2: reset high-speed USB device number 8 using dwc_otg
[  753.546649] mt76x2u 1-1.2:1.0: ASIC revision: 76120044
[  753.585972] mt76x2u 1-1.2:1.0: ROM patch build: 20141115060606a
[  753.768094] mt76x2u 1-1.2:1.0: Firmware Version: 0.0.00
[  753.776381] mt76x2u 1-1.2:1.0: Build: 1
[  753.783135] mt76x2u 1-1.2:1.0: Build Time: 201507311614____


root@RPi:~# lsusb
Bus 001 Device 004: ID 0e8d:7612 MediaTek Inc. Wireless
Bus 001 Device 006: ID 0bda:8153 Realtek USB 10/100/1000 LAN
Bus 001 Device 003: ID 0424:ec00
Bus 001 Device 008: ID 0e8d:7612 MediaTek Inc. Wireless
Bus 001 Device 007: ID 046d:c52b Logitech USB Receiver
Bus 001 Device 002: ID 0424:9514
Bus 001 Device 001: ID 1d6b:0002 Linux 5.4.154 dwc_otg_hcd DWC OTG Controller


root@RPi:~# iwinfo wlan0 info
wlan0     ESSID: "XXXXXXXX"
          Access Point: 00:C0:XX:B0:24:6D
          Mode: Client  Channel: 149 (5.745 GHz)
          Center Channel 1: 155 2: unknown
          Tx-Power: 13 dBm  Link Quality: 70/70
          Signal: -40 dBm  Noise: unknown
          Bit Rate: 526.6 MBit/s
          Encryption: WPA2 PSK (CCMP)
          Type: nl80211  HW Mode(s): 802.11nac
          Hardware: unknown [Generic MAC80211]
          TX power offset: unknown
          Frequency offset: unknown
          Supports VAPs: yes  PHY name: phy0

root@RPi:~# iwinfo wlan1 info
wlan1     ESSID: "XXXXXXXX"
          Access Point: 00:C0:XX:B0:25:32
          Mode: Master  Channel: 44 (5.220 GHz)
          Center Channel 1: 46 2: unknown
          Tx-Power: 19 dBm  Link Quality: 55/70
          Signal: -55 dBm  Noise: unknown
          Bit Rate: 200.0 MBit/s
          Encryption: WPA2 PSK (CCMP)
          Type: nl80211  HW Mode(s): 802.11nac
          Hardware: unknown [Generic MAC80211]
          TX power offset: unknown
          Frequency offset: unknown
          Supports VAPs: yes  PHY name: phy1


wlan0     Link encap:Ethernet  HWaddr 00:C0:CA:B0:24:6D
          inet addr:10.10.10.191  Bcast:10.10.10.255  Mask:255.255.255.0
          inet6 addr: fe80::2c0:caff:feb0:246d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:51 errors:0 dropped:0 overruns:0 frame:0
          TX packets:49 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:20239 (19.7 KiB)  TX bytes:10983 (10.7 KiB)

wlan1     Link encap:Ethernet  HWaddr 00:C0:CA:B0:25:32
          inet addr:10.10.30.1  Bcast:10.10.30.255  Mask:255.255.255.0
          inet6 addr: fe80::2c0:caff:feb0:2532/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:11100 errors:0 dropped:0 overruns:0 frame:0
          TX packets:32298 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1006435 (982.8 KiB)  TX bytes:44439222 (42.3 MiB)


root@RPi:~# iw dev wlan0 station dump
Station 70:4d:7b:11:47:ec (on wlan0)
        inactive time:  7612 ms
        rx bytes:       933977
        rx packets:     5111
        tx bytes:       158126
        tx packets:     1061
        tx retries:     486
        tx failed:      1
        beacon loss:    0
        beacon rx:      2258
        rx drop misc:   11
        signal:         -40 [-40, -48] dBm
        signal avg:     -40 [-40, -48] dBm
        beacon signal avg:      -40 dBm
        tx bitrate:     780.0 MBit/s VHT-MCS 8 80MHz short GI VHT-NSS 2
        tx duration:    60186 us
        rx bitrate:     866.7 MBit/s VHT-MCS 9 80MHz short GI VHT-NSS 2
        rx duration:    25408 us
        airtime weight: 256
        expected throughput:    68.389Mbps
        authorized:     yes
        authenticated:  yes
        associated:     yes
        preamble:       long
        WMM/WME:        yes
        MFP:            no
        TDLS peer:      no
        DTIM period:    1
        beacon interval:100
        short slot time:yes
        connected time: 232 seconds
        associated at [boottime]:       762.345s
        associated at:  1640808187503 ms
        current time:   1640808419098 ms

Station 44:03:2c:86:a5:1a (on wlan1)
        inactive time:  4 ms
        rx bytes:       1370904
        rx packets:     12191
        tx bytes:       44597670
        tx packets:     32764
        tx retries:     3333
        tx failed:      1
        rx drop misc:   0
        signal:         -56 [-61, -56] dBm
        signal avg:     -55 [-59, -55] dBm
        tx bitrate:     240.0 MBit/s VHT-MCS 5 40MHz short GI VHT-NSS 2
        tx duration:    1280055 us
        rx bitrate:     200.0 MBit/s VHT-MCS 9 40MHz short GI VHT-NSS 1
        rx duration:    93788 us
        airtime weight: 256
        expected throughput:    52.734Mbps
        authorized:     yes
        authenticated:  yes
        associated:     yes
        preamble:       short
        WMM/WME:        yes
        MFP:            no
        TDLS peer:      no
        DTIM period:    2
        beacon interval:100
        short preamble: yes
        short slot time:yes
        connected time: 1007 seconds
        associated at [boottime]:       57.991s
        associated at:  1640807483149 ms
        current time:   1640808489447 ms


root@RPi:~# lsusb -v -d 0e8d:7612

Bus 001 Device 004: ID 0e8d:7612 MediaTek Inc. Wireless
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.10
  bDeviceClass            0
  bDeviceSubClass         0
  bDeviceProtocol         0
  bMaxPacketSize0        64
  idVendor           0x0e8d
  idProduct          0x7612
  bcdDevice            1.00
  iManufacturer           2 MediaTek Inc.
  iProduct                3 Wireless
  iSerial                 4 000000000
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x004a
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          5 BT_Config
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           8
      bInterfaceClass       255
      bInterfaceSubClass    255
      bInterfaceProtocol    255
      iInterface              1 WiFi_If
      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     0x85  EP 5 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     0x08  EP 8 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     0x04  EP 4 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     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
Binary Object Store Descriptor:
  bLength                 5
  bDescriptorType        15
  wTotalLength       0x0016
  bNumDeviceCaps          2
  USB 2.0 Extension Device Capability:
    bLength                 7
    bDescriptorType        16
    bDevCapabilityType      2
    bmAttributes   0x0000f41e
      BESL Link Power Management (LPM) Supported
    BESL value     1024 us
    Deep BESL value    61440 us
  SuperSpeed USB Device Capability:
    bLength                10
    bDescriptorType        16
    bDevCapabilityType      3
    bmAttributes         0x00
    wSpeedsSupported   0x000e
      Device can operate at Full Speed (12Mbps)
      Device can operate at High Speed (480Mbps)
      Device can operate at SuperSpeed (5Gbps)
    bFunctionalitySupport   1
      Lowest fully-functional device speed is Full Speed (12Mbps)
    bU1DevExitLat          10 micro seconds
    bU2DevExitLat         180 micro seconds
can't get debug descriptor: Resource temporarily unavailable
Device Status:     0x0002
  (Bus Powered)
  Remote Wakeup Enabled

Bus 001 Device 005: ID 0e8d:7612 MediaTek Inc. Wireless
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.10
  bDeviceClass            0
  bDeviceSubClass         0
  bDeviceProtocol         0
  bMaxPacketSize0        64
  idVendor           0x0e8d
  idProduct          0x7612
  bcdDevice            1.00
  iManufacturer           2 MediaTek Inc.
  iProduct                3 Wireless
  iSerial                 4 000000000
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x004a
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          5 BT_Config
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           8
      bInterfaceClass       255
      bInterfaceSubClass    255
      bInterfaceProtocol    255
      iInterface              1 WiFi_If
      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     0x85  EP 5 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     0x08  EP 8 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     0x04  EP 4 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     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
Binary Object Store Descriptor:
  bLength                 5
  bDescriptorType        15
  wTotalLength       0x0016
  bNumDeviceCaps          2
  USB 2.0 Extension Device Capability:
    bLength                 7
    bDescriptorType        16
    bDevCapabilityType      2
    bmAttributes   0x0000f41e
      BESL Link Power Management (LPM) Supported
    BESL value     1024 us
    Deep BESL value    61440 us
  SuperSpeed USB Device Capability:
    bLength                10
    bDescriptorType        16
    bDevCapabilityType      3
    bmAttributes         0x00
    wSpeedsSupported   0x000e
      Device can operate at Full Speed (12Mbps)
      Device can operate at High Speed (480Mbps)
      Device can operate at SuperSpeed (5Gbps)
    bFunctionalitySupport   1
      Lowest fully-functional device speed is Full Speed (12Mbps)
    bU1DevExitLat          10 micro seconds
    bU2DevExitLat         180 micro seconds
can't get debug descriptor: Resource temporarily unavailable
Device Status:     0x0002
  (Bus Powered)
  Remote Wakeup Enabled


phy#3
        Interface wlan3
                ifindex 12
                wdev 0x300000003
                addr 00:c0:ca:b0:25:32
                ssid XXXXXXXXXXXX
                type AP
                channel 44 (5220 MHz), width: 80 MHz, center1: 5210 MHz
                txpower 20.00 dBm
                multicast TXQ:
                        qsz-byt qsz-pkt flows   drops   marks   overlmt hashcol tx-bytes        tx-packets
                        0       0       344     0       0       0       0       83561           366
phy#2
        Interface wlan2
                ifindex 6
                wdev 0x200000001
                addr b8:27:eb:0f:45:06
                type managed
                channel 1 (2412 MHz), width: 20 MHz, center1: 2412 MHz
phy#0
        Interface wlan0
                ifindex 9
                wdev 0x2
                addr 00:c0:ca:b0:24:6d
                ssid XXXXXXXXX
                type managed
                channel 149 (5745 MHz), width: 80 MHz, center1: 5775 MHz
                txpower 13.00 dBm
                multicast TXQ:
                        qsz-byt qsz-pkt flows   drops   marks   overlmt hashcol tx-bytes        tx-packets
                        0       0       0       0       0       0       0       0               0

This may be a power issue. Try inserting a powered USB hub between the Pi and the USB wifi adapters. Make sure that hub can provide enough power to each of the adapters.

Well, you were 100% correct. I had a 3amp power supply on it which I thought was enough but apparently the USB 2.0 ports only put out a combined 1200mA. Unplugging the gigabit ethernet adapter resolved all the errors - its been running beautifully all day without a single issue. I missed catching it 'cause I couldn't see the little thunderbolt that pops up on screen via SSH - thanks much for your input!

Glad that I was able to help!

If your problem is solved, please consider marking this topic as [Solved]. See How to mark a topic as [Solved] for a short how-to.

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