Hardware freeze: keyboard LEDs blink

cfgauss · l33t Joined: 18 May 2005 Posts: 726 Location: USA

This is a problem which used to happen rarely and now seems to happen twice a month. I'm not sure what the cause is.

The symptom is that my PS2 keyboard will freeze and two of its LEDs will blink synchronously. When this happens, the entire box freezes. The mouse doesn't work. KDE windows are not updated. I can't ssh to the box, etc. The only solution is a hard reboot (with accompanying file system repair, etc.) When the keyboard lights start blinking, I've replaced the keyboard by a known working PS2 keyboard and its LEDs start blinking. I.e. it's frozen as well.

Does this indicate that the PS2 hardware port on the motherboard is malfunctioning? If so, I'd assume I could solve the problem by using a USB keyboard.

Thanks for any debugging suggestions.

[SOLVED] The video card fan is dead. See below. [/SOLVED]
[UNSOLVED]
I now don't believe that the video card fan was the root of the problem. Today the keyboard froze right after booting. The CPU and graphic card temperatures were all pretty low, as indicated by gkrellm, so I don't think overheating was the cause. Only the keyboard froze (with blinking lights, etc.) The mouse and all other processes were running normally.

Is this an indication that the problem is with the PS2 keyboard hardware or the PS2 keyboard driver?

Thanks for any debugging suggestions.
[/UNSOLVED]

eccerr0r · Posted: Sat Jul 14, 2012 10:24 pm Post subject:

When this happens this means the kernel panicked. A serious problem occurred that the kernel could not recover from, so it freezes the state of the machine to make sure no additional corruption can occur.

Since it's frozen, it makes it a bit harder to debug. Ideally it would be nice to catch it in the act somehow to help debug.

Is there any specific thing you did that would trigger this freeze?
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cfgauss · l33t Joined: 18 May 2005 Posts: 726 Location: USA

eccerr0r · Posted: Sat Jul 14, 2012 10:42 pm Post subject:

Usually in this state, the machine does not sync, so if it did write anything to the disk it would not have made it.
Probably best to setup another machine and serial console into it, and make the kernel log to the serial console.

But if it's just doing an emerge, perhaps the machine overheated? What CPU is this (older AMD?) Could you try running a memtest program too, also perhaps check if your CPU fan is clean?

But yes, this usually means hardware issue, but software issues could also trigger...
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Intel Core i7 2700K/Radeon R7 250/24GB DDR3/256GB SSD
What am I supposed watching?

cfgauss · l33t Joined: 18 May 2005 Posts: 726 Location: USA

DirtyHairy · Posted: Fri Jul 27, 2012 7:46 am Post subject:

Software definitely is a possible culprit, and trying out a different kernel or provoking the panic without X running (to check whether graphics are related) won't hurt. However, the best thing would be to capture a log of the panic via serial or netconsole. This way, the backtrace might tell which parts of the kernel are involved in the panic.

cfgauss · l33t Joined: 18 May 2005 Posts: 726 Location: USA

depontius · Advocate Joined: 05 May 2004 Posts: 3526

Incidentally, at one point they had the LEDs blinking Morse code to tell you a little bit about the kernel panic you were having. I haven't done Morse code in some 40 years, so I wouldn't be a good to tell you. But if you have any ham radio friends, you might see if you can trigger this while he/she is watching. I also don't know how much information is being blinked out, what information, if it repeats, etc.
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DirtyHairy · Posted: Fri Jul 27, 2012 3:11 pm Post subject:

I've never done it myself, but take a look at Documentation/networking/netconsole.txt in the linux sources.