STM32MP13 - Jumbo Frames - Constrained MTU size problem

[jschneider]

Hi,

I am working on an Azure RTOS project, which requires jumbo frames capability. My current devkit is a MYD-YF13X to utilize 1 gigabit ethernet PHYs.

My goal is to receive 9000-byte packets, but I am not able to receive any bigger than ~2000 bytes.

Packets with size over 2kB are simply being ignored, as they wouldn't be transferred. The eth interrupts and respective receive complete callbacks are not being activated for them. 

I performed the following configuration:

I have also configured the YT8521-SH ethernet PHY to work with jumbo frames

I have also adapted the size of the buffers respectively.

At the end I worked with the OpenSTLinux with both STM32MP13-Devkit and MYD-YF13X. I wanted to resize the MTU of eth interface. With the ifconfig tool I wasn't able to set the MTU to 9000 bytes. Once again, it was constrained to 2000 bytes.

Why is the constraint set to ~2000?

I would be thankful for any advice and help.

Best,

J.Schneider

[jschneider · Accepted solution]

Hello,

I solved the problem.

I just had to reset RSF in ETH_MTLRXQxOMR.

Best,

J.Schneider

[unsigned_char_array]

Can you please share (some of) your code so others know how to do this too?

[jschneider]

Hi,

Of course, I can share a sample piece of code.

You might also need to consider the assumptions of my first post.

Best,

J.Schneider