[lug] debugging workstation issue

[Davide Del Vento]

Thanks to both of you.

Zan: it is indeed a systemd system and "journalctl -b -1" provides what I
was looking for. I don't see anything suspicious other than perhaps

Apr 09 13:23:43 buzzicone systemd[1]: Starting Message of the Day...
Apr 09 13:23:43 buzzicone systemd[1]: Started Message of the Day.

(and then the log ends). The time is around when the problem occurred and I
tried to trigger that live by e.g. opening a new shell, starting bash with
-l option, ssh'ing to localhost, triggering the screensaver. Nothing cause
it to happen.... so that is weird.

D Stimits: ssh'ing prior to the failure assumes that I have a spare system
to do that, which unfortunately at the moment I haven't (plus as I said it
sometimes happens at boot before I get a chance to ssh into it). Thanks for
the tip about unplugging and replugging USB devices, I will try that next
time!

Cheers,
Davide

On Thu, Apr 9, 2020 at 3:10 PM D. Stimits <stimits at comcast.net> wrote:

>
>
> On April 9, 2020 at 2:14 PM Davide Del Vento <davide.del.vento at gmail.com>
> wrote:
> Folks,
>
> My workstation, a desktop-sized server computer used as a desktop, is
> having a very annoying problem, which is even more severe these days that I
> have to rely to it for basically everything (so far the only thing I don't
> use it for is for when I use the restroom, but that may change soon)...
>
> Anyway, the problem is that sometimes at boot and sometimes after the
> screensaver is engaged the machine goes into a "dead" status. I suspect it
> can be an hybernation mode or something like that, which does not awake
> when I hit the keyboard, mouse or power button. A long press on the power
> button does trigger a reboot, with all the usual consequences of such a
> thing (possible files not closed, filesystem checks, loss of not-saved
> data, etc). When it is in this status, trying to ssh into it from another
> machine hangs with no response.
>
> It's been a long time since I debugged something like this and dmesg shows
> only messages since last reboot, which are clearly useless. Any clues on
> how to look at the logs immediately BEFORE that? Bonus points if you have
> any ideas on what might be going on or specifically what to look for.
>
>
>  Ssh in and run "dmesg --follow" prior to the failure. The computer which
> is displaying this will still be running.
>
> Tip: Often USB devices do not correctly handle or respond to low power
> mode events. If this is the case, then when mouse/keyboard fails to wake up
> the system, you might try to unplug and replug the mouse/keyboard and test
> again if you can now resume.
>
> PS: If I were more motivated I'd edit my window manager and display
> manager code and remove the option to manually sleep/suspend. I hate
> accidentally clicking that instead of log out or shut down or reboot.
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