No wifi device detected for WCN785x

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1

Hello, I have recently build myself a new computer, and when migrating to it I noticed that wifi device was not showing up. I have attempted to boot in to windows, where it was working successfully. I’m a little unsure of what is going on, so if anyone could help me with troubleshooting I would really appreciate it.

nmcli device
DEVICE   TYPE      STATE                   CONNECTION         
enp12s0  ethernet  connected               Wired connection 1 
lo       loopback  connected (externally)  lo                 

lspci -k | grep -A3 -i network
09:00.0 Network controller: Qualcomm Technologies, Inc WCN785x Wi-Fi 7(802.11be) 320MHz 2x2 [FastConnect 7800] (rev 01)
    Subsystem: Foxconn International, Inc. High Band Simultaneous Wireless Network Adapter
    Kernel driver in use: ath12k_pci
    Kernel modules: ath12k
0c:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8126 5GbE Controller (rev 01)

sudo dmesg | grep -i ath12k
[    5.223314] ath12k_pci 0000:09:00.0: BAR 0 [mem 0xdca00000-0xdcbfffff 64bit]: assigned
[    5.223338] ath12k_pci 0000:09:00.0: enabling device (0000 -> 0002)
[    5.223702] ath12k_pci 0000:09:00.0: MSI vectors: 16
[    5.223708] ath12k_pci 0000:09:00.0: Hardware name: wcn7850 hw2.0
[    6.479090] ath12k_pci 0000:09:00.0: chip_id 0x2 chip_family 0x4 board_id 0xff soc_id 0x40170200
[    6.479094] ath12k_pci 0000:09:00.0: fw_version 0x1105811c fw_build_timestamp 2025-03-11 07:08 fw_build_id QC_IMAGE_VERSION_STRING=WLAN.HMT.1.1.c5-00284-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3
[    6.761629] ath12k_pci 0000:09:00.0: ignore reset dev flags 0x200
[   11.877555] ath12k_pci 0000:09:00.0: failed to receive wmi unified ready event: -110
[   11.877983] ath12k_pci 0000:09:00.0: failed to start core: -110
[   11.880587] ath12k_pci 0000:09:00.0: qmi failed to send mode request, mode: 4, err = -5
[   11.880592] ath12k_pci 0000:09:00.0: qmi failed to send wlan mode off
2

Apparently its a kernel bug that has occurred after 6.12, so downgrading the kernel fixes the problem.
https://bugzilla.kernel.org/show_bug.cgi?id=220108

3

This is a firmware bug, not an kernel bug?

fix:

  nixpkgs = {
    overlays = [
      (self: super: {
        linux-firmware = super.linux-firmware.overrideAttrs (oldAttrs: {
          version = "20250410";
          src = pkgs.fetchzip {
            url = "https://cdn.kernel.org/pub/linux/kernel/firmware/linux-firmware-20250410.tar.xz ";
            hash = "sha256-aQdEl9+7zbNqWSII9hjRuPePvSfWVql5u5TIrGsa+Ao=";
          };
        });
      })
    ];
  };

Although a new firmware release is imminent.

2 Likes
4

Ohh, okay, ya not really familiar with how Linux kernel, and firmware is structured, what I can tell you is that what made it work was switching from this in my config

boot.kernelPackages = pkgs.linuxPackages_testing;

To this

boot.kernelPackages = pkgs.linuxPackages_6_12; # 6.12.31 at the moment

No other changes had to be made to the config. I have a lot of things going on so can’t test the overlay you send me, but hope it will help to anyone else who might be having this issue in the future.

5

this saved my sanity. until the new firmware is released this tip should go in the wiki or something.

2 Likes