Can bad USB devices cause system lockups?
 

I am having trouble with random hard lockups (ie screen freezes, can't ping or ssh to box, no capslock or numlock response on keybd) on 2 different boxes which I can't track down. Reset/Power button is the only cure. First was an old Celeron600 running FC5 and I have since upgraded (because of the freezes!) to a new MB with nforce chipset, new 1Gb memory, new HD and Athlon64 X2 running a fresh install of FC6 x86_64 and it has lockups too.

There are only 2 pieces of hardware that I used in both boxes...a PCI PCMCIA cradle with a Prism2 based wireless PCMCIA card plugged into it and a USB ISDN modem. I have swapped both cradle and wireless card with others known to work on other boxes so I think this hardware is OK. This also worked flawlessly on an old RH9 box. The only difference is that FC5/6 appears to load the orinoco module instead of the prism2 module that RH9 and other distros have used with this card. Could this be an issue?

So this leaves the ISDN modem, which is not working well ATM. Could a faulty USB modem (or any other faulty USB device) cause a system to lock up like this?

P

It is a possibility. The usb core is not the most stable part of the linux kernel by a long shot.

Also, USB has quite a bit of power, if your Modem is doing something stupid with that power, you may find that it is actually the motherboard shutting everything down!

The USB device could be the issue -- do you ever see random lockups when it is not being used? If the lockups only occur when the USB device is plugged in, then it seems reasonable to conclude that it is the culprit. OTOH, if the lockups occur regardless of whether the USB is connected or not, then you've got some sort of other problem, such as possible over-heating, bad RAM, a flaky PSU, etc.

Thanks for the replies. The lockups can be several days or a week apart or several per day, but I don't want to go without the internet for that long to test it :)

The modem is supplied by the company that provides the ISDN service, so I have to convince them there is something wrong with it so they will change it over. I haven't come across lockups caused by USB before so wanted to know if it had happened to others.

Just a thought. You are Aussie. Do you use Telstra Bigpond, if so, give it the old heave ho. I live in rural SA, my ISP is Internode over Agile, they use LINUX exclusively on their servers and are rolling out lots of Solar powered wireless towers in my region,($39.99\mnth for 512k feed and 20 Gb\mnth with throttleing on overs. Using Billion VOIP gateway routers with good firewalling and admin. Telstra are locked to MS Winslows and will try to tell you Linux will not work. All lies.
Good luck mate all the best shorty943.

If the USB device only gets its power from USB, there is a high chance the computer will malfunction. Buy a powered USB hub. Though the USB cable may have to be replaced.

When you upgraded your parts, you probably did not think of changing the power supply. The quality of the power supply plays an important role of keeping electronics working well. I recommend changing the power supply at the same time you are upgrading a motherboard or CPU. I suggest power supplies that have active power factor and universal voltage (no 120/240 volt switch).

I suggest asking for an Ethernet version.

Have you checked other broadband connections. In my area ISDN is more expensive than cable and DSL.

Shorty: yeh...I wish I could jump out of the Big Puddle. But I'm pretty rural on a farm in southern NSW. I know there is OneWire wireless in nearby towns but they are 25km or more away so are out of range. Same with ADSL, my exchange is over 10km away and there is no chance of ADSL getting installed in an exchange with only 30 or so users anyway. :( One-way satellite would require ISDN anyway and 2-way sat is too expensive and don't know how that would go with my dynamic DNS, web and mail servers etc. 3G wireless might be possible in the future if it ever gets cheaper. ISDN is $45/mnth 128/128kb unlimited up/download.

Thanks Electro, I did change the PSU too and the modem has it's own power, not from USB. I have contacted the telco (Telstra) and they are sending a tech out, so hopefully that will fix it.

Thanks,
P