Re: [PATCH ath-next] wifi: ath12k: change MAC buffer ring size to 4096

[Baochen Qiang <baochen.qiang@oss.qualcomm.com>]

On 10/20/2026 4:53 PM, Shawn Guo wrote:
> + linux-arm-msm
> 
> On Tue, Jun 09, 2026 at 08:13:58PM -0700, Yingying Tang wrote:
>> For WCN7850, MAC buffer ring size is updated to 2048 in
>> 955df16f2a4c3 ("wifi: ath12k: change MAC buffer ring size to 2048")
>> to increase peak throughput.
>>
>> But during the RX process, a phenomenon can still be observed where
>> the throughput drops by about 30% from its peak value and then recovers,
>> and this behavior repeats during RX.
>>
>> After increasing MAC buffer ring size to 4096, the data rate drop has
>> gone.
>>
>> Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00302-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.115823.3
>>
>> Signed-off-by: Yingying Tang <yingying.tang@oss.qualcomm.com>
> 
> FYI, in case someone else runs into this: with this change (merged in
> v7.3), WiFi on my Lenovo Yoga Slim 7x (X1E80100, WCN7850 hw2.0) stopped
> working with the older firmware that Debian trixie still ships
> (firmware-atheros 20250410-2):
> 
>   WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3
> 
> Probe and firmware download succeed, but every WMI command times out
> once the interface is brought up:
> 
>   ath12k_wifi7_pci 0004:01:00.0: wmi command 16387 timeout
>   ath12k_wifi7_pci 0004:01:00.0: failed to send WMI_PDEV_SET_PARAM cmd
>   ath12k_wifi7_pci 0004:01:00.0: failed to enable PMF QOS: -11
>   ath12k_wifi7_pci 0004:01:00.0: fail to start mac operations in pdev idx 0 ret -11
> 
> Bisecting ath12k between v7.2 and v7.3 lands on this commit, and
> reverting it on v7.3 brings WiFi back with the old firmware.
> 
> Unmodified v7.3 works fine after updating to the current linux-firmware
> image:
> 
>   WLAN.HMT.1.1.c7-00108-QCAHMTSWPL_V1.0_V2.0_SILICONZ_UPSTREAM-3
> 
> On Debian trixie that one is available from trixie-backports
> (firmware-atheros 20260916-1~bpo13+1).
> 
> So nothing needs fixing on the driver side. I'm just leaving this here
> so that anyone who sees "wmi command ... timeout" on WCN7850 after a
> kernel upgrade knows to update the firmware first.

Hi Shawn, thanks for reporting this. I just had a quick test
WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3 with the latest ath tree
(ath-202610191908), everything looks good, simple connection and ping pass, I don't see
any ath12k warning.

The firmware images I am using comes from the first commit adding WCN7850 firmware:

	fb04a7f4b750 ("ath12k: add new driver and firmware for WCN7850")

and the md5 values are:

linux-firmware/ath12k/WCN7850/hw2.0$ md5sum ./*
d3750b67b1013fe82358d0538fb131b0  ./amss.bin
c79c410d585360000c0490f16fda43e2  ./board-2.bin
73056f1d2aff886ce9bff313f455e963  ./m3.bin
d0ee61498bf1a205147cdbcf645391e7  ./Notice.txt

can you share the md5 values of your images? and have you ever tried the upstream mainline
kernel or the latest ath.git tree?