Beaglebone Black Instability With Ethernet Plugged In

[Apache14]

Hello all,

This is my first post , I have been attempting to get arch running on my Beaglebone Black and have run into a problem. If it attempt to boot it with no Ethernet cable everything works fine, however if an Ethernet is present at startup it will boot for about 5sec and then all LED's will switch off. I can "trick" it into booting by plugging the cable in ~10sec after the LEDs start flashing, however this will only work for a few moments (even if I switch to conservative CPU scaling).

Iv seen that in another thread that it could be attributed to insufficient power, I do not think this is the case here as iv tried two different 5v 2000mA power supplies with the same problem. I also cant see that its a problem with the SD card or Beaglebone itself as other distributions (such as ubuntu) boot fine.

If anyone could direct me to something else to try that would be amazing

Many thanks in advance,

Apache14

[photomankc]

Are you using a supply that imitates a USB port? If I use my USB battery in either the mini-usb port or the barrel connector it will do the lights-out deal midway through the boot. The issue is worse when I use an SD card as the boot media. Wireless dongles will also make that worse. I definitely have more issues in Arch with this than Angstrom. The Angstrom board will boot from the USB battery without issue.

The lights going out strongly suggest a power issue.

[Apache14]

Yeah I can see it being a power issue. But I know both of these can supply over 2amps at 5v. Tho i have only tested it through the micro usb port. Iv had both ubuntu and angstrom booting from sd with zero problems, it seems there is something majorly different in arch.

[photomankc]

Yeah, same for my battery, it can supply well over 1A as well. I cobbled up a USB -> Barrel cable and that seemed to improve things. It doesn't just go dark on me part-way through but the boot-up seems flakey. Sometimes it won't completely boot until after a reset with the barrel still plugged in. I don't have any issues from a wall-powered supply that was already just a barrel jack. It boots up fine from that.

My guess is that it has something to do with the 500mA limit on USB. So far all I can tell is that this seems to be true of any USB port I plug into, and not true for any standard wall-wart power supply I use instead. Down the road I'll be injecting 5V on the headers anyway so not a big deal but it would be nice if we could get all the default hardware online below the 500mA line.

[Apache14]

$this->bbcode_second_pass_quote('photomankc', 'i')t would be nice if we could get all the default hardware online below the 500mA line.

[kmihelich]

If the board is just powering off randomly, the cause is you are supplying insufficient power. As explained elsewhere, this is because the default CPU governor for our kernels is performance, which due to the constant high clock speed will require more power.

[Apache14]

$this->bbcode_second_pass_quote('kmihelich', 'I')f the board is just powering off randomly, the cause is you are supplying insufficient power. As explained elsewhere, this is because the default CPU governor for our kernels is performance, which due to the constant high clock speed will require more power.

[kmihelich]

I don't know if the USB port has a current limit, but I would assume it does. The amount of power that can be delivered to the board is also a function of the length of the USB cable. Total power will decrease as the length increases. Powering through a barrel connector, I simply cannot replicate your issues. I will try over USB later today.

Performance was an arbitrary default, and in nearly all cases it is the best choice as getting enough power to the board isn't an issue. Decisions in x86 Arch are also not the decisions made here, we are separate entities.

[kmihelich]

Just tested again using only the supplied USB cable connected to my desktop USB port, and the board works fine with ethernet booting off of eMMC. It does experience the powering off with the SD card also in place, so that extra load is likely what is tipping it over the edge. The Beaglebone White doesn't have any issue.

[photomankc]

Interesting observation. I cleared my eMMC and booted from the card instead because I was running out of space. Looks like it's right on the knife-edge then as it boots but with eMMC and no card you can get by on USB.