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SDK1.1 Freescale DPA Ethernet Driver JUMBO Frame issue

Question asked by Amrut Kulkarni on Jun 16, 2014
Latest reply on Jun 30, 2014 by Amrut Kulkarni

Hi All,


Currently i am using SDK1.1 source with P4040 processor which has Freescale's DPA Ethernet driver.

  1. When JUMBO frame are disabled i'm able to transfer max UDP datagram size upto 65507 bytes which is max UDP can handle and it working perfectly OK
  2. When JUMBO frames are enabled i can transfer only max of 16272 bytes and i see huge drop in the max UDP datagram size from 65507 to 16272 bytes.
  3. Bellow is the kernel config option :



For the test #1 & # 2  MTU size on bth the end is 1500 bytes. In test #2 only JUMBO Frame support was enabled in kernel as above


is this some bug it the DPA Ethernet driver ? How can i fix the issue ??

Just for the testing propose when i have set different MAX_FRAM_SIZE i get different UDP max datagram size

1.9600 - 16272 bytes

2.4500   24000 bytes

3.3000   28000 bytes


Please let me know if anyone has any hint/answer for above question

Thank you for your help and time !!