Linux X220 Spontaneous Reboots

[Don]

I'm not even sure this is a hardware question, but I have to start somewhere. Over the last several months, my machine intermittently spontaneously reboots. I cannot trace the behavior back to any new software or hardware installations (because I've made none except for 12.04 updates). It has never happened when I'm working on the machine, but it's not my main machine, so I don't use it for long stretches without a break.
I suspect that someone will ask me to post the logs from /var/log, and I'm happy to do that. But when I look in that directory, I see all sorts of log files with different extensions. for example, in files from the relevant time period (the machine spontaneously rebooted two or three days ago), there are files with the following patters of names:

dmesg.[#].gz
kdm.log.[#].gz
syslog.[#].gz

Which ones might contain clues to what's happening?

I've also tried running diagnostics, but it's almost impossible to do. When I boot the system, the logon screen is so dim I can't really see anything. I know to put in my password, of course, and then kde starts up and the screen brightens. (Wish I could do the same.) The keys that purportedly control screen brightness do not work before logon, and I can find nothing in System Settings that affects it.

Thanks in advance.

[oshunluvr]

IME, random reboots are always a hardware problem. The best way to determine this is if there is nothing logged just prior to reboot. In other words, if linux is doing the reboot, it will log it.

Re. the log files and various extensions: The current log file will end in .log, the one just prior will end in .log.1, and older ones (.2, .3, etc.) are automatically compressed into gzip archives, thus the .gz. I believe the older ones are eventually purged by date or something.

So the way to figure out what is causing this is to note as exactly as possible when the reboot occurs, then review ALL logs that have entries during that time period or just before.

Another possible cause of this might be your ACPI. Since you're already having screen brightness issues, that would be my first guess. I had an old desktop that the linux kernel would mis-read the CPU temp by applying some multiplier to the actual temp. and then shutdown because the temp. was too high (not really,of course). Once I booted it with "noacpi" option the shutdowns stopped. You might try that.

[Don]

Many thanks, Oshunluvr, for the quick reply. There was a spontaneous reboot Monday, Tuesday or Wednesday of this week (though I don't know which). I have the syslog files for that period of time, but even one of them exceeds the length that the forum allows. This makes me suspect that I am looking at the wrong files.

[oshunluvr]

The more exact you know when a reboot occurs, the easier it will be to track down the data. I suggest using the computer more until it happens again while you're using it.

[kubicle]

IME, random reboots are always a hardware problem.

That would be my first guess as well. I'd check the logs as already mentioned, just to be sure there isn't anything there (which would be a strong indication for a hardware failure).

One way to test hardware is to run memtest from grub for a few hours and see whether that causes reboots (it usually puts enough load on the system to bring out hardware problems...even if they are not memory related).

I believe the older ones are eventually purged by date or something.

Side note: it's not really (strictly) date based, it's logrotate (the software that handles log rotation) configuration that defines how many backlogs are kept for specific logs until the oldest is removed.

[Buddlespit]

I would like to point out that my wifes desktop used to freeze and reboot running Win7, which was fixed by installing Kubuntu 13.04. Hers was a software issue, not a hardware issue.

kubicles suggestion about running memtest for a few hours is a damned good idea

[oshunluvr]

I would like to point out that my wifes desktop used to freeze and reboot running Win7,

Yes, computers like air conditioners don't work well with windows open!

[Buddlespit]

Yes, computers like air conditioners don't work well with windows open!

[Don]

Yes, computers like air conditioners don't work well with windows open!

1. Amen!
2. There has been a new development, namely my recalling that the X220 has never spontaneously rebooted at home. So I've taken it home for a few days. So far, no spontaneous reboots, but I'm going to give it a few days more. If that continues, I suppose my next step is to bring it back to the office and plug it in first to a different power strip on the same socket, then to the original power strip in a different socket, and finally to the substitute strip on a different socket. I do not think it can be from some sort of signal coming from the University's network a) because my desktop never spontaneously reboots, and b) even if something were coming, it should only reboot my Windows (I apologize) VM, because the machine itself runs Kubuntu, and the University's network won't accept Linux machines. (The University, which generally is a pain in the . . . , recently instituted a system-wide policy of locking all machines after ten minutes of inactivity. I found a work-around for that. Such a policy may make sense for computers in public areas, but for those in attended or locked offices, it makes no sense at all.)

[oshunluvr]

Geez, they sound as bad as the Federal Government. You should point out to them that if they switched to Linux instead of Windows they could reduce their security concerns and save money to boot!

[Don]

Geez, they sound as bad as the Federal Government. You should point out to them that if they switched to Linux instead of Windows they could reduce their security concerns and save money to boot!

Oshunluvr,
Well, now you have some idea of what I'm up against! BTW, I named my work-around program "Defeat ____ University IT." All it does is to simulate a one-pixel mouse movement every nine minutes, so the system never perceives sufficient inactivity to trigger the u's policy.

Actually, it's worse than the federal government. The university is constantly strapped for money, but wastes it right and left. Sure, Linux makes more sense. That's probably why we haven't switched to it (that, and that the IT folks we now have don't know much about Linux, so there's a certain amount of job-security-instinct interfering).

Thanks for letting (helping) me vent. I feel much better. I will post updates on what's happpening with the X220 after I have some more data.