Raspberry Pi loses ethernet

Here's one suggestion from the RasPi Troubleshooting Wiki: you may be getting a burst of activity which overflows USB kernel memory.

I suggest getting a UART adapter cable that you can plug onto the 3.3V UART pins on the GPIO connector.  That way you can talk to RasPi without going through the LAN9512, which has likely crashed.  Here's a thread on the topic chez RasPi.

Well, I don't have that much knowledge in that region. Can I do nothing at software level?

Also, from the little I know about hardware, it seems to me that many of the soldered parts of my Pi are cold joints (they do not look shiny, but kind of white).

Again, I do not know much about this, so here is a photo of my Pi.

I hope the unit I have arriving tomorrow does not look like that, as you are quite right those are bad solder joints. I have the tools to fix mine if it comes to that but who ever is built your unit certainly should have failed it at the QC stage and sent it back for rework.

Mike

And now it decided to work again and find the network... (no changes made whatsoever)

Can anyone suggest something for mr to do to troubleshoot?

(general response, not to you only, I'm new here)

It probably aren't cold solder joints. Lead free solderings look different than ordinary ones.

I have read about problems with the solderings of one of the xtals (X1 or X2) Due to that the oscillator sometimes stops.

If you would have a keyboard and screen connected, you might be able to check the logfiles for abnormallities.

I assume you already tried another ethernet cable to rule that out. Connecting to another ethernet port might be worth testing as well.

See what /var/log/syslog says when that happens.  Whether you are using wired or wireless, if you start getting errors about its built-in ethernet, that can also interrupt anything else on USB.  The first one I got did that more often, and 2nd 2 would also do that at random periods of time.  Installing all updates regular updates did NOT help: sudo apt-get update && sudo apt-get dist-upgrade -y

What did help was doing rpi-update.  I don't think I have had that problem with any of them since doing that.  For example my 1st "troublesome" one has no problems running headless with only mini-WiFi attached:

efflandt@raspberrypi ~ $ uptime

10:30:28 up 2 days, 10:23,  1 user,  load average: 0.04, 0.08, 0.06

efflandt@raspberrypi ~ $ lsusb

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp.

Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.

Bus 001 Device 004: ID 0bda:8176 Realtek Semiconductor Corp. RTL8188CUS 802.11n WLAN Adapter

For rpi-update see https://github.com/Hexxeh/rpi-update/

If you have any trouble with wget not resolving ipv6 add following to /etc/wgetrc: inet4_only = on (that begins with small eye)

You also need to sudo apt-get install git-core, which rpi-update will tell you if you have not installed that.

I found out that every loss of networking occurs when my router does a NTP Date/Time update and afterwards sends an ACK to the raspberry. It does not happen immediately after the NTP update, but when the ACK is sent. I do not know much about routers, but have managed to "solve" it by resetting both the router and the raspberry at the same time. My router is a very old piece of equipment of Pirelli ( ! ).

Just putting it here if anyone has any thoughts on the matter.

I've had a similar experience when using a power supply which wasn't the best quality.  If you have another power supply kicking around which is over 700mA I would give that a shot before diving into the troubleshooting process to deeply.

My power supply is OK, I have measured the TP1 and TP2 connectors to 4.99 volts. I have also tried two others and had the same issue. I do not beieve it is the power supply.

I've tried all these options, changed power supplies (5v 2.1A), run rpi-update etc etc but still the problem persists. My conclusion is that there is either a serious h/w or driver bug. I did notice en route that there is an interaction between the lan and usb connections, eg unplugging a usb device would cause a reboot, having the lan and usb mouse connected on boot and the mouse doesn't work.  At the moment I'm running with only a lan connection, no others, connecting in via ssh or vnc, so the lan has to work.  On the whole a complete mess! At the moment I'm running without a case to see if there is an overheating problem; initial conclusion is that the lan stays up for longer but eventually drops out.  I'll eliminate other potential sources of problems, h/w, cables, routers etc since these aren't a problem for any of the other systems I run, including an early RasPi.  What I will do next is run the SD card in my old RasPi and if the problem doesn't show up then my conclusion is a h/w or driver problem in the recent board (it's about 1 year old). If rpi-update does install new driver/chip firmware then either that has a bug or there's a bad joint, bad component or some such on my board and I assume on others who have experienced the same conditions