Re: Stack trace when starting iwd with Intel BE200 M.2 Wi-Fi+BT card

["Diederik de Haas" <diederik@cknow-tech.com>]

On Thu Sep 3, 2026 at 2:59 PM CEST, Diederik de Haas wrote:
> I have a FriendlyElec NanoPC-T6 LTS (arm64, RK3588 SoC) and plugged in
> its E-key slot an Intel BE200 card. I'm using TF-A + U-Boot as firmware
> and bootloader, not something with ACPI support.
>
> That's probably why I'm getting these warnings in dmesg:
> ```
> [   11.313596] ACPI: <n/a>: failed to evaluate _DSM 2c176672-0b22-294b-814f-75e4dd26b5fd rev:0 func:0 (0x1001)
> [   11.313641] ACPI: <n/a>: failed to evaluate _DSM 2c176672-0b22-294b-814f-75e4dd26b5fd rev:0 func:0 (0x1001)
> ```
>
> My kernel does have ``CONFIG_ACPI=y``, but it's not used on this device.
>
> When I start iwd.service, I get the following stack trace:
>
> ```
> [12144.572968] ------------[ cut here ]------------
> [12144.572984] WARNING: net/wireless/nl80211.c:10730 at nl80211_get_reg_do+0x244/0x270 [cfg80211], CPU#6: iwd/2361
> ...
> [12144.604286] ---[ end trace 0000000000000000 ]---
> [12145.058595] ACPI: <n/a>: failed to evaluate _DSM bf0212f2-788f-c64d-a5b3-1f738e285ade rev:0 func:0 (0x1001)
> ```
>
> Despite the stacktrace, the wireless connection does work:
> ```
> root@nanopc-t6-lts:~# iwctl station wlan0 show
>                                 Station: wlan0
> --------------------------------------------------------------------------------
>   Settable  Property              Value
> --------------------------------------------------------------------------------
>             Scanning              no
>             State                 connected
> 	    ...
>             RxMode                802.11ax
>             RxMCS                 10
>             TxMode                802.11ax
>             TxMCS                 7
>             TxBitrate             1225100 Kbit/s
>             RxBitrate             2161300 Kbit/s
>             ExpectedThroughput    1020936 Kbit/s
> ```
>
> Similar results and stacktrace with kernel 6.18, 7.1 and 7.2, so it's not
> a recent regression.
>
> I also have a NanoPC-T6 Plus, which is quite similar, with an MediaTek MT7925
> M.2 Wi-Fi+BT card and there I do not get the ACPI msgs or the stack trace.

I also have an Intel AX210 M.2 card and I plugged that into that same
NanoPC-T6 LTS and there I do NOT get the stack trace.
I do get the same kernel warning as with the BE200NGW card:

```
root@nanopc-t6-lts:~# dmesg | grep ACPI
[    0.265591] ACPI: Interpreter disabled.
[    0.285103] pnp: PnP ACPI: disabled
[   11.047559] ACPI: <n/a>: failed to evaluate _DSM 2c176672-0b22-294b-814f-75e4dd26b5fd rev:0 func:0 (0x1001)
[   11.047579] ACPI: <n/a>: failed to evaluate _DSM 2c176672-0b22-294b-814f-75e4dd26b5fd rev:0 func:0 (0x1001)
[   11.295741] hci0: No support for bluetooth device in ACPI firmware
[   13.026720] hci0: ACPI-BT: No ACPI support for Bluetooth device
[   13.026745] Bluetooth: hci0: No support for BT device in ACPI firmware
[  119.634515] ACPI: <n/a>: failed to evaluate _DSM bf0212f2-788f-c64d-a5b3-1f738e285ade rev:0 func:0 (0x1001)
root@nanopc-t6-lts:~# iwctl station wlan0 show
                                 Station: wlan0
--------------------------------------------------------------------------------
  Settable  Property              Value
--------------------------------------------------------------------------------
            Scanning              no
            State                 connected
	    ...
            RxMode                802.11ax
            RxMCS                 4
            TxMode                802.11ax
            TxMCS                 3
            TxBitrate             29200 Kbit/s
            RxBitrate             432300 Kbit/s
            ExpectedThroughput    26328 Kbit/s
```

Not very impressive Wi-Fi speed, but alas.
I actually bought the BE200NGW and (later) AX210 card for Bluetooth.
Both perform poorly/terrible on that front, while the Intel 8265/8275 card
in my *amd64* laptop works great, including Bluetooth.
My laptop does have a BIOS/UEFI firmware with ACPI support.
Is ACPI support in boot firmware a requirement?

Cheers,
  Diederik