davebiffuk
Posts: 2
Joined: Thu Sep 05, 2013 9:30 am

network drops after some time, bug?

Thu Sep 05, 2013 9:49 am

I'm seeing my Pi's network drop after some time, anything from a few hours up to two weeks. It's lightly loaded, running 3 one-wire temperature sensors, a USB webcam, and a 16x2 LCD display screen. The sensors and webcam are queried once a minute, the LCD is updated every ~15 seconds. There are no other devices attached (no keyboard or USB disk etc). The power supply is a genuine RS one.

Before the network drops, kern.log starts logging:

Sep 4 13:55:07 davepi kernel: [1268085.366967] smsc95xx 1-1.1:1.0: eth0: Failed to read register index 0x00000114
Sep 4 13:55:07 davepi kernel: [1268085.367018] smsc95xx 1-1.1:1.0: eth0: Error reading MII_ACCESS

and then fills up with lots of:

Sep 4 15:47:11 davepi kernel: [1274809.262470] uvcvideo: Failed to set UVC probe control : -110 (exp. 26).
Sep 4 15:47:17 davepi kernel: [1274814.892624] smsc95xx 1-1.1:1.0: eth0: Failed to write register index 0x00000014
Sep 4 15:47:17 davepi kernel: [1274814.892672] smsc95xx 1-1.1:1.0: eth0: Failed to write HW_CFG_LRST_ bit in HW_CFG

and then soon after, the network stops working, although the Pi is running because it's able to update the LCD screen.

It's running kernel
Linux davepi 3.6.11+ #528 PREEMPT Tue Aug 20 00:25:53 BST 2013 armv6l GNU/Linux

and firmware
Aug 20 2013 00:41:29
Copyright (c) 2012 Broadcom
version 18e3e93a3ae0765ca25e4fe511f59f14396afcaa (clean) (release)

although the problem was there with previous versions too.

I've seen this with an original Pi and a more recent (512MB) model, so I'm thinking it's a kernel or firmware bug. Has anyone else seen this sort of behaviour? Any suggestions for how to proceed with diagnosing it? TIA!

technoducky
Posts: 62
Joined: Sat Jan 26, 2013 7:29 pm
Contact: Website

Re: network drops after some time, bug?

Fri Sep 06, 2013 8:58 am

I have had a similar problem, however in my case I diagnosed it as a power issue.
My Pi was switching a load which was powered from the same supply as the PI (not through the Pi), which I believe caused a voltage drop that affected the network controller but not the BCM, as the Pi kept running but the FDX and 100 lights dropped out for around 1 second (also my program hung as it was attempting to make a HTTP request at the same time).

In short, check your power consumption.

davebiffuk
Posts: 2
Joined: Thu Sep 05, 2013 9:30 am

Re: network drops after some time, bug?

Mon Sep 09, 2013 12:03 pm

Thanks, that's interesting. The current (pardon the pun) power supply is a 1200mA RS unit which I bought with the original Pi. I've replaced it with a 2000mA one. If that doesn't help I'll try adding a powered USB hub (though it seems like overkill just to run a cheap webcam). Let's see...

Return to “Troubleshooting”