LAN8720 Custom SOM Issue

[NPal.2]

We have custom SOM which has been designed with STM32MP157C.

We are using the OpenSTLinux 3.0.0 as of now as the distribution running on it.

In case of LAN PHY interfacing we are using LAN8720.

There is a strange behavior , upon I can see the below message in top.

This process is hampering the cpu performance. When running GUI based application I can see definite lag which occurring because of this.

The issue completely random earlier but now pretty consistent.

Any ideas what might be happening here?

Any leads are highly appreciated TIA

[OlivierK · Accepted solution]

Hi NPal.2 (Community Member)

It may be linked to the PHY interrupt when rising edge is detected on phy_intr_i input, causing a ETH0 global interrupt. it can be cleared when this register is read. you can try to mask out the phy interrupt using ETH_MACIER->PHYIE=0 to see if it makes any change + investigating towards the LAN8720 status registers. Otherwise you need to find the source causing the interrupt in the ETH_MACISR.

Rgds,

Olivier

[NPal.2]

@OlivierK​ Thanks for the response. We have root caused it. Posting another query around that on forum soon.

[OlivierK]

Hi NPal.2 (Community Member)

Thanks for your answer. Could you share the root cause? That may help others on the community.

Regards,

Olivier