Ethernet only working in Gigabit mode (not 100Mbit/s)

I have a Gigabit ethernet card in my primary development computer. When I connect the Mini-ITX Zynq board directly to that (with static IPs on both), it works fine (testing with "ping <address>". However, if it connects through a 10/100Mbit/s switch, it fails to work. Similarly, another development computer with only a 10/100Mbit/s ethernet card directly connected does not work. This makes me conclude that ethernet in anything less than 1Gbit/s mode on the Mini-ITX does not work. I am using the stock standard microSD to boot up. I have also built up my own Linux kernel and image, which also has exactly the same issue.

I also have a Zedboard. With the stock standard SD to boot up, this does work in 100Mbit/s mode through the switch, and with the 100Mbit/s ethernet card in the development computer.

Is this a limitation of the hardware, or is it a software configuration thing (in the kernel?)? If it is configurable, how do I make it work in 100Mbit/s mode? I have never heard of a Gigabit ethernet device not working with lesser speeds before. It seems like quite a limitation that would affect a number of people!

0 Former Member over 11 years ago

Additional info: In uboot (pressed the 'any' key to stop autoboot), I did set the static IP using "setenv serverip <address>" and "setenv ipaddr <address>", then "ping <otheraddress>", and it did work in 100Mbit/s mode. Resetting and attempting the same ping within Linux fails in 100Mbit/s, as expected. This suggests the hardware is capable of working at slower link speeds, but something in Linux is not configured correctly.
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0 Former Member over 11 years ago

Hello Sam,

Sorry for the slow reply, it took a little while to assemble the equipment and duplicate the problem. You are correct the Out Of Box Linux only links correctly to a 1 Gig Ethernet link. The Mini-ITX hardware is fine, it is an issue with PetaLinux 2013.10.

I have verified that the Mini-ITX Ethernet link works correctly with PetaLinux 2014.2. We do have PetaLinux 2014.2 BSP files on the Mini-ITX 'Reference Designs/Tutorials' page: http://zedboard.org/support/design/2056/17

You can follow the instructions in UG977 from Xilinx on how to create a new project. You could also just un-compress the BSP files and copy the boot.bin and uimage.ub files and replace those on your microSD card for a quick test.

-Gary
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0 Former Member over 11 years ago

Thanks Gary. I hope to test the PetaLinux 2014.2 boot files soon.
The funny thing is that I built my own Linux kernel using OpenEmbedded and the latest meta-xilinx layer: http://git.yoctoproject.org/cgit/cgit.cgi/meta-xilinx/. It has the same faulty Ethernet behaviour, which I thought was strange, as I would have expected it to be fixed in that repository.
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0 Former Member over 11 years ago in reply to Former Member

Sorry, that's not quite right. I switched to using the kernel from: https://github.com/Xilinx/linux-xlnx (because I couldn't get the PCIe slot working with OpenEmbedded). Which should still include all the latest fixes, so it's still strange the Ethernet isn't working there either.
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0 Former Member over 11 years ago in reply to Former Member

Gary, do you happen to know what sources/repositories are used to make PetaLinux?
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0 Former Member over 11 years ago in reply to Former Member

Hi,
I just had the same Problem, and it is related to the Devicetree.
Once I changed the values of the phy entry to the ones given in the
2014.2 design it worked:
                                phy0: phy@7 {
-                                       compatible = "marvell,88e1116r";
+                                       compatible = "marvell,88e1510";
                                        device_type = "ethernet-phy";
-                                        reg = <7>;
+                                        reg = <0>;
+                                        marvell,reg-init=<3 16 0xff00 0x1e 3 17 0xfff0 0x0a>;
                                } ;
                        } ;
whether I should also change the phy@7 to a phy@0 I am currently investigating.
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0 Former Member over 11 years ago

this setting will program PHY LEDs in DUAL LED MODE 3, with open drain outputs, is that what you intended todo?

My guess is that the LEDS are not connected in dual mode on the ITX board.
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