MSI issues - WiFi6 - ath11k support in 5.15 using backported single MSI vector support from 5.17rc1

Hello Toradex Developer Community,

I’m currently working on integrating a WiFi 6 module (Qualcomm Atheros QCN9024/9074) with a Toradex iMX8 SoM. I’ve observed that native support for this module isn’t present in the kernel version that Toradex provides (5.15).

To overcome this limitation, we have successfully backported single MSI vector support introduced in the 5.17rc1 kernel. This involved using patches available at:

Two hunks from a specific patch (Patch Details) did not apply cleanly. However, we were able to resolve the issue. The function causing the mismatch was ath11k_pci_enable_msi vs. ath11k_pci_alloc_msi.

Despite removing the pci=nomsi option from the kernel command line, the lspci output:

Capabilities: [50] MSI: Enable- Count=1/32 Maskable+ 64bit-

indicates that the MSI (Message Signaled Interrupts) capability is present (Maskable+ 64bit- ), but not currently enabled (Enable- ). The Enable- suggests that MSI support is disabled for the device.

We’re also noticing some irregularities in the lspci output for the WiFi 6 module, particularly a “degraded” status in link speed and width:

LnkSta: Speed 2.5GT/s (downgraded), Width x1 (downgraded)

I’m wondering if anyone has experience dealing with this, or knows of any compatibility issues between the iMX8 and WiFi 6, specifically related to MSI and the PCI bus. Is there a known reason why MSI vectors are disabled by default on Toradex SOMs?

Additionally, if there is a dedicated technical support line or Tier 3 support, that would also be very helpful.

Thank you for your time and expertise.

root@06875011-0000039:~# modprobe ath11k_pci
root@06875011-0000039:~# iw dev
Interface wlP1p1s0
ifindex 10
wdev 0x100000001
addr ee:58:68:63:fa:60
type managed
txpower 0.00 dBm
Interface wlp1s0
ifindex 7
wdev 0x1
addr a6:4a:02:48:ff:8c
type managed
txpower 0.00 dBm
root@06875011-0000039:~# dmesg | grep ath11k
[64268.119924] ath11k_pci 0001:01:00.0: BAR 0: assigned [mem 0x62000000-0x621fffff 64bit]
[64268.128002] ath11k_pci 0001:01:00.0: enabling device (0000 → 0002)
[64268.134745] ath11k_pci 0001:01:00.0: MSI vectors: 1
[64268.139664] ath11k_pci 0001:01:00.0: qcn9074 hw1.0
[64268.475835] ath11k_pci 0001:01:00.0: chip_id 0x0 chip_family 0x0 board_id 0xff soc_id 0xffffffff
[64268.484718] ath11k_pci 0001:01:00.0: fw_version 0x270206d0 fw_build_timestamp 2022-08-04 12:48 fw_build_id QC_IMAGE_VERSION_STRING=WLAN.HK.
[64268.601494] ath11k_pci 0001:01:00.0: leaving PCI ASPM disabled to avoid MHI M2 problems
[64269.498817] ath11k_pci 0001:01:00.0 wlP1p1s0: renamed from wlan0

Hi @tigerblue !

Sorry for the delay.

I brought up your topic internally already and I will let you know here once I have information to share with you.

Best regards,