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WiFi (SDIO) disconnects on i.MXRT1176 correlated with Qt/QML UI complexity

Hi Team,

We are currently working on an instrument cluster that features screen mirroring. In our architecture, a companion mobile app streams frames over Wi-Fi to our host MCU. The data is received via an SDIO-connected Wi-Fi module, decoded using FFmpeg, and rendered on the display. We are utilizing lwIP for our network stack and Qt for MCUs for the cluster HMI.

System Specifications:

Host MCU: NXP i.MX RT1176
Wi-Fi Module: u-blox MAYA-W161 (SDIO interface)
Display: LCDIFV2 (Parallel RGB Interface)
OS: FreeRTOS

The Issue: We are experiencing intermittent Wi-Fi disconnections that appear to be directly tied to graphical load. The Wi-Fi drops only occur when the display is running a resource-heavy GUI(featuring numerous elements and animations). When we switch to a lightweight UI, the Wi-Fi connection remains perfectly stable.

Kindly guide us to sort out this issue.

Regards,

Vignesh

Re: WiFi (SDIO) disconnects on i.MXRT1176 correlated with Qt/QML UI complexity

Hi @Vignesh_VInayak, hope you are doing well.

Since image processing requires high CPU usage and large memory footprint, it is intended that for GUI-related applications, one of the two cores is dedicated to managing the interface. Would you please clarify if your implementation approach uses the two cores? Is there enough stack dedicated to each thread?

Additionally, would you please share logs with debug logging enabled for the Wi-Fi stack, in order to further analyze the state of the Wi-Fi thread? To enable the debug logs, could you please enable the "CONFIG_WLCMGR_DEBUG" & "CONFIG_WIFI_SDIO_DEBUG" macros in the wifi_config.h header file?

Re: WiFi (SDIO) disconnects on i.MXRT1176 correlated with Qt/QML UI complexity

Hi @RomanVR ,

Thanks for getting back to me so promptly.

Please find the requested details and logs below:

At present, our project only uses the Cortex-M7 core; the M4 core is not being utilized.
Yes, all threads have sufficient stack allocated. We also confirmed this using the FreeRTOS stack overflow hook function, and no overflow is occurring.
I've attached the log file with the suggested macros enabled. In the log, everything appearing after the final wlcm log consists of our application logs, which simply print the some random frame size whenever a Wi-Fi packet is received. As you can see, the logs stop at a certain point — that's where the Wi-Fi disconnect occurs. At the moment of disconnection, we don't see any logs from either wlcm or SDIO.

Best regards,
Vignesh.

Re: WiFi (SDIO) disconnects on i.MXRT1176 correlated with Qt/QML UI complexity

Hi @Vignesh_VInayak,

Would you please clarify if after the disconnect occurs, does the rest of the application, including the display, continue to function normally? If it's the case, would you please share your thread priority configurations?

Related to the previous questions, could you please share the FreeRTOS runtime stats of the running threads?

For this you will need to enable "configGENERATE_RUN_TIME_STATS" in FreeRTOSConfig.h file and define a task to call periodically the FreeRTOS API "vTaskGetRunTimeStats" and print the result to the terminal. This will provide useful information on the CPU usage of each thread and narrow down the root cause of the Wi-Fi disconnections. Related to this, as display applications cause high CPU load, it is highly recommended that a dual-core architecture is implemented to ensure proper execution of high-load applications.