ath12k driver on Debian 12 - High ping latency and MLO support query on 6.11rc7

[Benoit Masson]

Hello ath12k developers,

I'm testing the ath12k driver on Debian 12 with a custom 6.11rc7
kernel for an M2 QCNCM865 card. While generally stable, I'm
encountering two issues:

1. High ping latency/jitter:
- ath12k: 3.5ms to 55ms (40ms jitter)
- Intel AX211 (same setup): ~4ms LAN, ~6ms internet (stable)
- AP: TP-Link BE800 (6GHz band) - Tested with various OFDMA, MIMO, and
MLO settings

2. MLO support:
- When connected via MLO, performance mirrors 6GHz-only connection
- Doesn't appear to utilize all three bands

Questions:
1. Are there any recent patches addressing the latency issue for
kernel 6.11rc7?
2. Is MLO fully supported by Linux/Qualcomm for this hardware? I'm
willing to test any proposed solutions or gather additional data if
needed.

Thank you for your ongoing work on the driver. Best regards,
Benoit



lshw output:
           *-network
                description: Ethernet interface
                product: Qualcomm Technologies, Inc
                vendor: Qualcomm Technologies, Inc
                physical id: 0
                bus info: pci at 0000:02:00.0
                logical name: wlp2s0
                version: 01
                serial: 4c:82:a9:XX:YY:ZZ
                width: 64 bits
                clock: 33MHz
                capabilities: bus_master cap_list ethernet physical
                configuration: broadcast=yes driver=ath12k_pci
driverversion=6.11.0-rc7 firmware=N/A ip=192.168.1.169 latency=0
link=yes multicast=yes
                resources: irq:97 memory:dc600000-dc7fffff

lspci output
02:00.0 Network controller: Qualcomm Technologies, Inc WCN785x Wi-Fi
7(802.11be) 320MHz 2x2 [FastConnect 7800] (rev 01)
Subsystem: Foxconn International, Inc. WCN785x Wi-Fi 7(802.11be)
320MHz 2x2 [FastConnect 7800]
Flags: bus master, fast devsel, latency 0, IRQ 97, IOMMU group 14
Memory at dc600000 (64-bit, non-prefetchable) [size=2M]
Capabilities: [40] Power Management version 3
Capabilities: [50] MSI: Enable+ Count=16/32 Maskable+ 64bit-
Capabilities: [70] Express Endpoint, MSI 00
Capabilities: [100] Advanced Error Reporting
Capabilities: [148] Secondary PCI Express
Capabilities: [158] Transaction Processing Hints
Capabilities: [1e4] Latency Tolerance Reporting
Capabilities: [1ec] L1 PM Substates
Kernel driver in use: ath12k_pci
Kernel modules: ath12k