SysRq, Ethernet, and USB

I’ve been getting this error message a lot:

[ 624.229701] SysRq : HELP : loglevel(0-9) reBoot Crash terminate-all-tasks(E) memory-full-oom-kill(F) kill-all-tasks(I) thaw-filesystems(J) saK show-backtrace-all-active-cpus(L) show-memory-usage(M) nice-all-RT-tasks(N) powerOff show-registers§ show-all-timers(Q) unRaw Sync show-task-states(T) Unmount force-fb(V) show-blocked-tasks(W)

It’s been happening while I try to get ethernet working on the BeagleBone Black. My set up is that I have internet sharing on my laptop and I connect the BBB to the laptop via ethernet. I followed Josh Anderson’s instructions here to get this operating. Sometimes it does not work, and while debugging this, I’ve removed and reinserted the ethernet cable from the BBB. That’s when I get these crashes. Rebooting helps, but doesn’t actually fix the issue (and seems like overkill).

When I leave the ethernet cable out completely and ping [google.com](http://google.com/)', I [predictably] get no sysout back. When I plug it in and ping google.com’, I get this sysout:

`PING google.com (173.194.43.6) 56(84) bytes of data.’

But I don’t get any response back from google.

Also, if I reboot the bone without any ports connected and then plug in a simple usb camera, the usb camera light turns on. But if I then either re-insert that usb plug or add in the ethernet plug, the light no longer operates, but there is a video0 in /dev/. And if I start up the BBB with an ethernet attached and then try to insert a usb camera, I get no signal that the camera is there. There is no additional line in /dev/ and the light does not turn on.

While looking around for similar cases, I found this review that mentions:

  1. The USB port doesn’t have a working hotplug detection. That means that if you plug an USB device in the USB port, it will be only detected once, if you remove the USB device, the USB port will stop working. I’ve been told that they are working on it. I haven’t been able to find a workaround for it.

Has that problem been fixed? Any insight into these issues would be greatly appreciated. I’m running the Angstrom distro that came with my board (arrived two days ago).

to get this operating. Sometimes it does not work, and while
debugging this, I’ve removed and reinserted the ethernet cable from
the BBB. That’s when I get these crashes. Rebooting helps, but

It crashes after SysRq?

When there is a problem, I see SysRq warnings pop up.

doesn’t actually fix the issue (and seems like overkill).

Worse than overkill it doesn’t actually help!

What does it actually do it reboot?

When I leave the ethernet cable out completely and ping [google.com](http://google.com)', I [predictably] get no sysout back. When I plug it in and ping
google.com’, I get this sysout:

`PING google.com (173.194.43.6) 56(84) bytes of data.’

But I don’t get any response back from google.

Also, if I reboot the bone without any ports connected and then plug
in a simple usb camera, the usb camera light turns on. But if I then
either re-insert that usb plug or add in the ethernet plug, the light
no longer operates, but there is a video0 in /dev/. And if I start up
the BBB with an ethernet attached and then try to insert a usb
camera, I get no signal that the camera is there. There is no
additional line in /dev/ and the light does not turn on.

While looking around for similar cases, I found this
review<http://armin762.wordpress.com/2013/04/28/the-new-beaglebone-black-and-gentoo/

that mentions:

  1. The USB port doesn’t have a working hotplug detection. That
    means that if you plug an USB device in the USB port, it will be
    only detected once, if you remove the USB device, the USB port will
    stop working. I’ve been told that they are working on it. I haven’t
    been able to find a workaround for it.

Has that problem been fixed? Any insight into these issues would be
greatly appreciated. I’m running the Angstrom distro that came with
my board (arrived two days ago).

Can you point me to the bug report for this? I would like to follow
it’s progress too. It sounds like a kernel config problem and not a
hardware problem.

I’m not sure if there is an official one filed; I came across that on Armin’s blog. If you’re asking me to publish a report, how do I do that?

If your ping command is showing the IP address it seems DNS is actually resolving; so maybe it is some firewall stuff on your laptop.

Can you ping your laptop from your BBB ? If you can you have network running but your laptop isn’t routing/NATing your BBB.

I can ping from laptop to BBB. How do I change the routing to the BBB from my computer?