I've been investigating an issue we're having with our i.MX53 based device. Essentially what we're observing is that sometimes on some devices when they boot up the fec seems to have issues sending tx packets to the phy. I wrote a simple loopback test in which I set up the fec for external loopback and enabled the loopback feature on the phy. I then sent out 20 packets and watched for the packets on the rx. With this test I see that when the device boots into this bad state I don't get all the packets. I believe it's a tx issue since I have also tried pinging another computer and I've observed that some packets just don't ever make it.
It seems odd that I don't see this problem on all devices, just some. And it doesn't happen every time they power up. Some devices seem to have this problem 10% of start ups, while others are less.
Has anyone experienced this issue or have any ideas of where to look?
I'm currently using the 3.14 kernel with rmk fec patches. I've experienced this same issue in the 2.6.35 kernel as well.