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I accidentally discovered that the Raspberry Pi 3 can run on 2.1A, so I constantly get the Lightning Bolt in the corner, indicating that I'm going to go over the limit it will let me.

So, to consume less "power" I decided I should not use the UI. I don't want to disable GUI on startup, so I init 4'd. That causes a freeze saying Welcome to PIXEL with plymouth-start.service in the bottom left corner. Then because it's worth a shot, I kept trying to kill Xorg. Didn't work either, but what I'm focusing on is init 4 freezing with plymouth.

Darth Vader
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Scott B.
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  • As Milliways points out, all SysV runlevels (except halt and single user) are the same on Debian/Raspbian. You've been reading some documentation that was stale before the Pi was even invented. Anyway, there's a sort of bug here in that ideally this shouldn't do anything (it may to keep some kind of backward compatibility, see man init and man telinit, obviously it isn't very useful). – goldilocks May 27 '17 at 10:44

2 Answers2

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This has NOTHING to do with the (alleged) current rating of the power supply.

Not using the GUI will have negligible impact on the current drawn by the Pi.

Jessie DOES NOT use runlevels (except 0, 1, 7) all others are mapped to these.

The Voltage is too low and/or the cables are inadequate. See Raspberry Pi Power Limitations

Milliways
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Slight correction to the above answer: Jessie using systemd does not use runlevels.

If, however you are a luddite or not a fan of (the hydra-like) systemd (like myself) you may have chosen to stick with the System V init which is a bit more mature (by a couple of decades?) like what I've done - however even then you may not see much difference when you use sudo telinit # where # is a different run-level number (or letter?).

On my system, I see the only difference for the run-levels 2 to 5 is that 2 does not run lightdm i.e. the system that starts X and presents a GUI login screen does not run in that normal level which is the sort of thing I think you are wanting - to configure the differences there are various tools and for the RPi I see that I have sys-rc-conf(8) which has both a CLI and a GUI - so read the man page for that or do an apropos run level and see what else might be relevant.

Actually the reason I do not use systemd also has a connection to the fact that my RPi is running with an RPi specific UPS and I have written a daemon that communicates vital information to init ("um, the power has failed and the battery is running out - shutdown now please before it is completely exhausted!") via it's /run/initctl interface and the systemd source code for this, instead of doing anything with the messages merely logs: Received UPS/power initctl request. This is not implemented in systemd. Upgrade your UPS daemon! - and I can't be arsed to do so when the init API is well defined and works perfectly well for me... 8-)

SlySven
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