Resolved: Re: Laptop: External monitor, keyboard, and mouse "disabled" -- how re-enable without rebooting?
Aside: I meant to update this a little while ago, but better late than never?
(Except that some of the details are more vague, now ;-(
To partially summarize / restate the problem: after setting up a (new to me)
laptop (a Dell Inspiron 1501) on a new to me Belkin F1DS104J 4-port USB / PS/2
KVM switch, I found that if I switched to another computer for a significant
period (not timed, but definitely happened if left overnight), on switching the
KVM back to the laptop, the laptop appeared dead (no signal to the (KVM)
monitor).
I thought the problem was that the laptop was "suspending" and then not
"unsuspending" when I switched to it and pressed something on the (KVM)
keyboard or moved / clicked the mouse.
Later (with the help of my son) we noticed that the KVM keyboard and mouse
were live (he was watching the laptop screen and noticed that my actions on
the keyboard and mouse showed up on the laptop screen. So, we realized that
the problem was not that the laptop was in suspend, but that, somehow, the KVM
monitor was not active. We eventually determined that when either monitor
(the KVM monitor or the laptop screen) went into power saver mode, on doing
something on either keyboard or mouse, the laptop screen reactivated, but the
KVM monitor did not.
So, we made several changes to the settings for the Display and Monitor, in
almost a shotgun approach (in other words, several times I made more than one
change before retesting, and I'm not absolutely sure which were essential and
which were not. I try to list them all here:
---+++ Computer ==> System Settings ==> Hardware ==> Display and Monitor
On this configuration screen, there was the possibility to designate either the
laptop screen or the external (the KVM) monitor (E325BV-FMD(VGA-0)) as the
primary display, or neither.
I had problems when either display was set as the primary -- the current
setting (which seems to work) has neither display designated as primary.
+++---
---+++ Computer ==> System Settings ==> Hardware ==> Power Saving
Note that there are settings for use On AC Power, On Battery, or On Low
Battery -- for now I am primarily interested in the settings under AC power.
Settings (that seem to work:
Dim the screen after 5 minutes
Screen Energy Saving: Switch off after -- unchecked the box.
Button events handling: When laptop lid closed: Do nothing, Even when an
external monitor is connected
When power button pressed: < Prompt log out dialog
There are other settings (e.g., Run script, Wireless) which I didn't fool
with.
+++---
On Thursday, February 06, 2020 10:45:57 AM rhkramer@gmail.com wrote:
> I've installed Buster on a Dell Inspiron 1501 laptop. I have it connected
> to an external monitor, keyboard, and mouse via a KVM switch.
>
> I thouight all was well, but now, a day later (with the KVM switched to
> other computers), switching the KVM back to the laptop, the external
> monitor, keyboard, and mouse are no longer enabled. (They still work fine
> for any of the other computers.)
>
> I suspect that if I reboot the laptop, or maybe even if I logout of the
> current user and back in, I might get the external monitor, keyboard, and
> mouse re-enabled, but I don't really want to do either -- as is often the
> case, I have various files and such open and to an appropriate place that I
> don't want to lose (nor have to re-establish).
>
> So, that leads to two questions:
>
> 1. Is there a way to re-enable the external monitor, keyboard, and mouse
> without doing something like rebooting?
>
> 2. Is there a way (a setting to change) to keep the problem from recurring
> in the future?
>
> One more "extra credit" OT question (which I can ask in a future thread if
> no one responds here) -- how can I tell whether the Buster installation is
> using X or Wayland?
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