WiFi 9098 driver freezes on Linux system with preempt-rt

[hieule]

Hello!

In one project, we are developing an embedded board running a i.MX 8M Plus and WiFi 9098 chip. For our application, RT-patch is needed. Unfortunately, the WiFi card freezes consistently in a simple iperf3 test.

We suspect that the RT patch changes locks and causes this problem. A log file is attached below.

Please help!

Best,

HL

P/S: I did some quick look, this does not seem to be asked before. Otherwise, please help point me to the related questions and answers

[hieule]

So the kernel RCU stall still happens with the newer driver version (in https://www.nxp.com/webapp/Download?colCode=PCIE_UART-BT.p136.19-MXM5X17366.P7.V0V1-MGPL&appType=lic...)

Anything I can do to narrow down the scope of the issue?

[cdoumenc · Accepted solution]

After checking with internal team members, our wifi driver doesn't support real time linux.

Indeed, when RT-patch is applied to the standard linux kernel, it becomes real time but our wifi driver is not real time, so it can't respond to requests from Real Time kernel.

[cdoumenc]

Which interfaces configuration are you using for wifi and bt (https://www.nxp.com/products/wireless/wi-fi-plus-bluetooth-plus-802-15-4:WIFI-BLUETOOTH?tid=vanwifib...) ? (PCIe + UART) or (SDIO + UART) ?
Because, if using HW config (PCIe + UART), you can use the more recent SW version "PCIE-WLAN-UART-BT-9098-U16-X86-17.68.1.p136.19-17.26.1.p136.19-MXM5X17366_P7_V0V1-MGPL" you will find here

If using config (SDIO + UART), you can use the more recent SW version "SD-WLAN-UART-BT-9098-LNX_5_15_71-IMX8-17.92.1.p136.13-17.92.1.p136.13-MM5X17366.P5-MGPL" you will find here

[hieule]

Thanks. It's PCIE+UART. I'll try the driver that you posted.

[hieule]

The driver in use appears to be MXM5X17345.p3

As mentioned, we have our own Linux BSP version (based on linux-imx but with some customisations including RT-patch)

[cdoumenc]

I edited my previous post to fix the first link

[hieule]

Thank you for the support!

The first link does not work for me. Essentially, we develop our own board, and it's required some BSP customisation. Our Linux is based on nxp-imx/linux-imx branch 5.15.

I'll check out the driver that you posted.

[cdoumenc]

Hello,
Could you tell which Linux BSP version you are using among those available (see page https://www.nxp.com/design/software/embedded-software/i-mx-software/embedded-linux-for-i-mx-applicat... )?
And which WiFi driver version are you using ? Are you using the most recent one (see https://www.nxp.com/products/wireless/wi-fi-plus-bluetooth-plus-802-15-4/2-4-5-ghz-dual-band-2x2-wi-... ?