[HowTo] reboot / turn off your frozen computer: REISUB/REISUO

[a_0vi]

Well, I did what you said.
my chrome was opened with 3/4 tabs. But after the reboot, when I opened Chrome again, a dialogue showed “Chrome didn’t shutdown correctly. Restore all the tabs?”
I mean, Is it normal? A not gentle shutdown causes the same dialogue to appear when opening Chrome. Should this gentle shutdown cause the same for Chrome?

[andreas85]

This only prevents damage to your file system. (which can result in an unbootable system, or worse)

Each program is responsible for keeping its data safe. And chrome obviously does it well.

[freggel.doe]

If chrome did not shutdown correctly after getting the TERM signal (E in the sequence) it either did not react on it or did not have enough time because the I (KILL signal) followed too quickly.

[siberianhusky]

Thanks for your post.

@NewGuard

alt+prt sc + r
letting go of r and prt sc and holding alt key the whole time…
then
prt sc + e

(Note: I test this when PC is not frozen)
But looks like I don’t need that much key presses. When I pressed ptr sc +e, the computer is “soft rebooted”, screen turned black, some texts flashes, I was brought to the login window. Logged in and posted this.

Is there any issue for my setup? Or it’s because I already input the key sequences mentioned above:

@Fabby

Now lightly tap these keys waiting between 1 second (fast, new machines) and 6 seconds (older or resource-starved machines¹) in-between keypresses : R E I S U B

(this had no effect after I pressed)

My PC got frozen after clicked hibernate, and I hard reset it, because those key sequences not working. Will try the REISUB next time.

[dmt]

@siberianhusky

But looks like I don’t need that much key presses. When I pressed ptr sc +e, the computer is “soft rebooted”, screen turned black, some texts flashes, I was brought to the login window.

I’d say it’s closer to logging out.

E sends SIGTERM which causes everything (except init) to close gracefully, this includes the display manager, which then restarts and you’re presented with the login screen.

The I may also do it, as it sends SIGKILL which causes everything (except init) to be killed ungracefully.

Whether the display manager restarts or not depends on how borked your system is.

If you’re back at the login screen you shouldn’t need to continue, but if you do
finish the sequence it should reboot. Make sure you wait after S, as it syncs all mounted filesystems and this can take a while, at least with HDDs.

[hro]

Wouldn’t it be better to just enable the required SysRq functions?

The Arch Wiki page states that kernel.sysrq=244 is sufficient for REISUB.