Disable keyboard...err... keyboard suspend resume and power?

eccerr0r

Okay, need yet another software fix for a hardware problem.

My wireless keyboard is crap. Well, my house is crap. I have one heck of a lot of random interference that sometimes my wireless keyboard interprets as a shutdown or suspend event and acts accordingly.

While the shutdown is very annoying, the suspend is more so, mainly because one of my DVBs does not suspend properly and comes up in a dazed and confused state when resuming. So then I have to completely reboot to make it come back up.

Now, completely disabling suspend/resume not exactly what I want : if I stopped mythtv and rmmod the module, (but leave the other DVB as is) then I would be fine with suspending...so that's not the route I want to go. Besides it doesn't stop the poweroffs.

So is there a way in Gnome to disable the one-button keyboard98 suspend/resume and poweroff "buttons" without disabling suspend/resume/poweroff using the mouse through the GUI, echo mem > /sys/power/state, and surely do not want to prohibit typing sudo shutdown -h now/systemctl halt ... ?
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Anon-E-moose · Posted: Tue Mar 30, 2021 7:14 pm Post subject:

acpi stuff? look in /etc/acpi/default.sh
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dbtx · Tux's lil' helper Joined: 20 Jan 2020 Posts: 117

Are you using X? You could disable XF86Sleep and XF86PowerOff according to the accepted answer here.

eccerr0r · Posted: Tue Mar 30, 2021 9:21 pm Post subject:

I suspect mucking the acpi routines may affect the GUI routines.
As I wrote the post I was thinking about xmodmap and mapping those scancodes away...luckily I am using X so this should work?

For now: xmodmap -e 'keycode 124 = X' -e 'keycode 150 = S' and hope it stops sleeping/shutting down...(and dumps random S's and X's )

Now for Wayland...
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eccerr0r · Posted: Wed Jun 16, 2021 2:42 pm Post subject:

FSCK. still suspending somehow.

New experiment: change VT out of X11 and to a login screen... Try THAT, keyboard! (since login does not accept keyboard sequences...)

If only the dvb driver would suspend/resume properly...
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eccerr0r · Posted: Tue Jul 06, 2021 1:24 pm Post subject:

Okay this is ultimately annoying:
Since nothing has apparently stopped the suspends and poweroffs, let's now plug into systemd-logind:

/etc/systemd/logind.conf:

HandlePowerKey=ignore
HandleSuspendKey=ignore

Now lets see if weirdness occurs.... This is NOT what I want because ACPI handles the chassis power key too and goes through systemd-logind that way... so this is also effectively disabling my front panel switch. Ugh. These are the days where having all power keys handled through libinput is annoying, but really it's probably just the keyboard that's annoying.
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Hu · Moderator Joined: 06 Mar 2007 Posts: 21602

If you have successfully blocked the system from suspending at all, that gives you some freedom to experiment with finding exactly how the keyboard is able to suspend your system when the key is pressed (or a bogus keypress is detected). Do the keyboard keys generate the same ACPI event as a soft tap on the power button? If yes, perhaps you could patch your kernel to make those keys inert.

You could also go with a wired keyboard, which would make the interference irrelevant.

eccerr0r · Posted: Wed Jul 07, 2021 1:32 pm Post subject:

Wired keyboard and HTPC just doesn't quite go together... :(

Really I should find the source of the noise... though it still could be external.
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Hu · Moderator Joined: 06 Mar 2007 Posts: 21602

You said this was a MythTV system with DVB recorders, so I thought it was the backend, not the frontend. Are you running both frontend and backend on the same hardware? Wouldn't that require having the system on at any time a program you wish to record is broadcast?

If you need to fix this in software, I think the first step is understanding which layer(s) of the stack can distinguish between a soft tap on the power button and the keyboard key. Once we know which layers can tell them apart, then we can identify which layer is best to apply the distinction that ignores the keyboard and not the power button.

eccerr0r · Posted: Wed Jul 07, 2021 4:37 pm Post subject:

Correct, the frontend and backend are the same machine (though I have other frontends around ). Technically even the backend can suspend for a few hours per day when no expected recordings need to take place, but yes it still needs to pick up EPG data and some broadcasters are stingy, giving only a few hours at a time.

And yes need to figure out where the event is coming from. Systemd is not being kind and telling me who pressed the button, but at least it is indicating an event is happening versus some hardware failure and causing the machine to crash without any notice ...
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eccerr0r · Posted: Fri Aug 06, 2021 2:51 am Post subject:

Well I did the ultimate test of checking where the events are coming from:

- I disconnected the keyboard and ran keyboardless (since recently I've only been watching remotely instead of using the TV monitor).

After 20 odd days, no shutdowns or suspends where it had been at least a weekly event... I guess it's pretty certain at this point that the keyboard seems to be the source of the event... now how to stop it without the drastic removal of keyboard...
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dbtx · Tux's lil' helper Joined: 20 Jan 2020 Posts: 117

Bizarre. Is there any way the BIOS/UEFI is doing it? I mean, do sleep/power keys do anything while you're looking at a bootloader?

But I think your first assertion is probably correct-- the keyboard is crap. It seems to me that if the wireless function is indeed the root cause, then either it doesn't encrypt keystrokes or that encryption is pretty poor. If the wireless function is not the root cause, then maybe its microcontroller is malfunctioning, which may or may not itself be a result of local interference.

That (finally) reminds me-- did you ever open the keyboard and look for liquid damage? Or to be less specific, does the problem still appear if the wireless receiver is connected but the keyboard is completely disabled (as in, it has removable batteries)?

After so much of being trolled-by-the-physics-department, I'd have already got something brand new that runs in a different frequency range... or infrared

...but that's just me.

eccerr0r · Posted: Fri Aug 06, 2021 2:28 pm Post subject:

Crap or nonexistent encryption is probably the root cause. I definitely get random trash keystrokes once in a while too, so it's not completely out of the question it's generating poweroff or suspend operations as well...

Now how to get it ignored has been the question...
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