16.04: Alt+tab keyboard shortcut crashes system

[Dáire Fagan]

I have gotten used to not using alt+tab to switch program but I would like to start using it again, instead of using the less functional alt+¬, or manually navigating to docky to select the specific window of the specific program I want to display.

This because when I use alt+tab, often my desktop will freeze. I know at least sometimes alt+F2, r, and enter does not resolve, it, REISUB may also not work and I will have to hard reset.

I searched for a fix before but could not find, is there one please?

Ubuntu 16.04, Gnome 3.28.2.

[Dáire Fagan]

Bump.

[tea for one]

I do not know why your Alt+Tab is misbehaving but I can help you with a link about REISUB.

Ubuntu does not ship with REISUB fully enabled.

Here is a method to enable the process by editing a file:-


sudo nano /etc/sysctl.d/10-magic-sysrq.conf

Then change the number in line 26 from 176 to 244 i.e. kernel.sysrq = 244

I found the solution at this site https://digitalfortress.tech/debug/w...buntu-freezes/ and the information was in section 3.

By the way, the last letter in the process B reboots your system, sometimes you may want to power off completely by substituting the B for an O

Best wishes

[Dáire Fagan]

I do not know why your Alt+Tab is misbehaving but I can help you with a link about REISUB.

Ubuntu does not ship with REISUB fully enabled.

Here is a method to enable the process by editing a file:-


sudo nano /etc/sysctl.d/10-magic-sysrq.conf

Then change the number in line 26 from 176 to 244 i.e. kernel.sysrq = 244

I found the solution at this site https://digitalfortress.tech/debug/w...buntu-freezes/ and the information was in section 3.

By the way, the last letter in the process B reboots your system, sometimes you may want to power off completely by substituting the B for an O

Best wishes

I have put that in place, thank you very much for the tip.

Is there anything I can do about the alt+tab crashing, perhaps this is more a Gnome issue than Ubuntu?

[mörgæs]

Is there anything I can do about the alt+tab crashing, perhaps this is more a Gnome issue than Ubuntu?

A live boot of Ubuntu 18.04 will show if a more recent Gnome works better.

[Holger_Gehrke]

Have you tried switching to a virtual terminal when the GUI hangs ? When decrypting a large mega.nz download, my system seems to hang to the point of the mouse pointer not moving and the clock in the taskbar standing still. I can still use ctrl-alt-F1 to get to the first virtual terminal (although the switch can take a minute or longer) and check memory and system load on the command line. It's mostly a matter of memory or rather lack of it leading to massive swapping, mega's JavaScript seems to use several times the size of the downloaded file during decryption; when it's done the system slowly returns to normal responsiveness.

If you can get to a VT you could just restart your display manager ('systemctl restart lightdm' or whatever your display manager is; lightdm on XUbuntu and Lubuntu, could be something else on other flavours). This would close the complete GUI session and return you to the login screen (on VT7). You would loose any unsaved work but the risk of system corruption is a lot lower.

Holger