No wifi device detected for WCN785x

Help
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.

3 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
6

WiFi on Qualcomm QCNCM865 / WCN785x is still broken on linux firmwares 20250627 and linux 6.14+ (latest firmware is working on linux 6.13.x).

Downgrading to firmware 20250410 causes annoying freezes on my computer with latest kernels, even if wifi starts working again.

Did anyone found a patch or a workaround beyond simply staying on linux 6.12 or 6.13 ?

7

It Works For Me™ (on Snapdragon T14s) with NixOS-provided linux firmware, but I am running Ubuntu kernel 6.16-rc4.

Can you try kernelPackages = pkgs.linuxPackages_testing; ?

8

Still broken for me even on 6.18.0-rc3 if anyone will have any updates on whats going on under the hood it would be nice to hear anything at this point honestly

9

I’m also running vanilla 6.18.0-rc3 (linuxPackages_testing) on my T14s these days, with linux-firmware-20251111.

The T14s carries a Qualcomm® Wi-Fi® 7 NCM825A.

journalctl -b snippets:

kernel: ath12k_pci 0004:01:00.0: BAR 0 [mem 0x7c400000-0x7c5fffff 64bit]: assigned
kernel: ath12k_pci 0004:01:00.0: enabling device (0000 -> 0002)
kernel: ath12k_pci 0004:01:00.0: MSI vectors: 16
kernel: ath12k_pci 0004:01:00.0: Hardware name: wcn7850 hw2.0

kernel: ath12k_pci 0004:01:00.0: qmi dma allocation failed (7012352 B type 1), will try later with small size
kernel: ath12k_pci 0004:01:00.0: chip_id 0x2 chip_family 0x4 board_id 0xff soc_id 0x40170200
kernel: ath12k_pci 0004:01:00.0: fw_version 0x110cffff fw_build_timestamp 2025-06-25 09:26 fw_build_id QC_IMAGE_VERSION_STRING=WLAN.HMT.1.1.c5-00302-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.115823.3
kernel: ieee80211 phy0: copying sband (band 1) due to VHT EXT NSS BW flag
systemd-networkd[830]: phy0: Saved new wiphy: index=0
systemd-networkd[830]: phy0: Found device: /sys/devices/platform/soc@0/1c08000.pci/pci0004:00/0004:00:00.0/0004:01:00.0/ieee80211/phy0
systemd[1]: Starting Load/Save RF Kill Switch Status...
systemd-networkd[830]: phy0: Found rfkill device: /sys/devices/platform/soc@0/1c08000.pci/pci0004:00/0004:00:00.0/0004:01:00.0/ieee80211/phy0/rfkill0
systemd-networkd[830]: wlan0: Saved new link: ifindex=2, iftype=ETHER(1), kind=n/a
systemd-networkd[830]: wlan0: Saved original MTU 1500 (min: 256, max: 2304)
systemd-networkd[830]: wlan0: Saved permanent hardware address: <redacted>
systemd-networkd[830]: wlan0: Saved hardware address: <redacted>
systemd-networkd[830]: wlan0: Saved IPv6 link-local address generation mode: eui64
systemd-networkd[830]: wlan0: Flags change: +MULTICAST +BROADCAST
systemd-networkd[830]: wlan0: link pending udev initialization...
systemd-networkd[830]: wlan0: nl80211: received new_interface(7) message: iftype=station, ssid=n/a
systemd-networkd[830]: wlan0: udev initialized link
systemd-networkd[830]: wlan0: Found driver: ath12k_pci
systemd-networkd[830]: wlan0: Link state is up-to-date
systemd-networkd[830]: wlan0: State changed: pending -> initialized
systemd-networkd[830]: wlan0: Found matching .network file, based on potentially unpredictable interface name: /etc/systemd/network/wlan0.network
systemd-networkd[830]: wlan0: Configuring with /etc/systemd/network/wlan0.network.
systemd-networkd[830]: wlan0: State changed: initialized -> configuring
systemd-networkd[830]: wlan0: link_check_ready(): link is not activated.
systemd-networkd[830]: wlan0: link_check_ready(): link is not activated.
systemd-networkd[830]: Setting '/proc/sys/net/ipv6/conf/wlan0/disable_ipv6' to '0'
systemd-networkd[830]: No change in value '0', suppressing write
systemd-networkd[830]: Setting '/proc/sys/net/ipv6/conf/wlan0/use_tempaddr' to '2'
systemd-networkd[830]: No change in value '2', suppressing write
systemd-networkd[830]: Setting '/proc/sys/net/ipv6/conf/wlan0/accept_ra' to '0'
systemd-networkd[830]: Setting '/proc/sys/net/ipv6/conf/wlan0/proxy_ndp' to '0'
systemd-networkd[830]: No change in value '0', suppressing write
systemd-networkd[830]: Setting '/proc/sys/net/ipv4/conf/wlan0/promote_secondaries' to '1'
systemd-networkd[830]: No change in value '1', suppressing write
systemd-networkd[830]: wlan0: link_check_ready(): link is not activated.
systemd-networkd[830]: wlan0: Requested to activate link
systemd-networkd[830]: wlan0: Requested configuring of the DHCPv4 client.
systemd-networkd[830]: wlan0: Requested configuring of the DHCPv6 client.
systemd-networkd[830]: wlan0: Requested configuring of the IPv6 Router Discovery.
systemd-networkd[830]: wlan0: Requesting static address (n/a): <redacted>/48 (valid forever, preferred forever), flags: n/a, scope: global
systemd-networkd[830]: wlan0: Setting addresses
systemd-networkd[830]: wlan0: link_check_ready(): link is not activated.
systemd-networkd[830]: wlan0: link_check_ready(): link is not activated.
systemd-networkd[830]: wlan0: link_check_ready(): link is not activated.
systemd-networkd[830]: wlan0: link_check_ready(): link is not activated.
systemd-networkd[830]: wlan0: link_check_ready(): link is not activated.
systemd-networkd[830]: wlan0: link_check_ready(): link is not activated.
systemd-networkd[830]: wlan0: link_check_ready(): link is not activated.
systemd-networkd[830]: wlan0: link_check_ready(): link is not activated.
systemd-networkd[830]: phy0: The radio transmitter is unblocked.
systemd-networkd[830]: wlan0: Bringing link up
systemd[1]: Started Load/Save RF Kill Switch Status.
systemd-networkd[830]: wlan0: Flags change: +UP +RUNNING
systemd-networkd[830]: wlan0: Link UP
systemd-networkd[830]: wlan0: link_check_ready(): static addresses are not configured.
systemd-networkd[830]: wlan0: Flags change: -RUNNING

What exactly is still broken for you?

10

Ahh slip past me.
Ya I verified its no longer an issue, turns the WiFi chip on my motherboard has decided to die, and that was a recent source of headache for me.