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#1 2017-09-28 13:46:18

forty-two
Member
Registered: 2017-06-30
Posts: 21

Automatic printing of '^@' after login after installing xorg and lxde.

Installed ArchLinux: fine.
Ran command [pacman -Syu]: fine.
Installed xorg-server, xorg-xinit, xorg-clock, xterm, xorg-twm + [auto-detected dependencies]: fine.
Installed proprietary nvidia drivers: fine.
Tested by [startx]: got three instances of xterm, fine.
Installed the whole [lxde] group: fine.
--> Forgot to add [exec startlxde] in ~/.xinitrc: oops!
Ran command [systemctl enable lxdm.service]: fine.
Rebooted: OK.
--> On reboot all the booting log flashes by and probably xserver is started: COMPLETE BLANK SCREEN.
--> Used [ctrl+alt+F2]: Got tty2 login prompt, BUT:
           automatically the null character ^@ gets printed in the login prompt at nearly 1sec intervals.
           Can remove them using backspace, but impossible to type password in this manner.

Used arch installation disk to [arch-chroot] into my installation, ran [systemctl disable lxdm.service]: Service deleted, phew !
Reboot into installation: startx doesn't get executed, BUT annoying printing of ^@ goes on. Cannot login in this state.

ALL installation of above mentioned things was done while logged in as root.

Help. Thanks in advance!

Last edited by forty-two (2017-09-28 13:50:28)

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#2 2017-09-28 15:42:57

eddilein
Member
From: Germany / Bavaria
Registered: 2008-08-06
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

Sorry,

I don't understand...

How can you try to startx if you can not log in?

By the way, why to changeroot? A simple booting from the install media would have been enough.

But as I said, I don't understand?!?

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#3 2017-09-28 16:00:13

forty-two
Member
Registered: 2017-06-30
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

eddilein wrote:

Sorry,

I don't understand...

How can you try to startx if you can not log in?

By the way, why to changeroot? A simple booting from the install media would have been enough.

But as I said, I don't understand?!?

Installation ≠ install media. The systemctl code caused the lxdm.service to be started at boot which I turned off by chrooting into my installation via the install media (since I cannot login to my installation directly due to those annoying ^@ s).

Last edited by forty-two (2017-09-29 08:48:21)

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#4 2017-09-28 16:21:37

Trilby
Inspector Parrot
Registered: 2011-11-29
Posts: 29,525
Website

Re: Automatic printing of '^@' after login after installing xorg and lxde.

The same problem has been reported before:
https://bbs.archlinux.org/viewtopic.php?id=207880
https://bbs.archlinux.org/viewtopic.php?id=207359
Unfortunately, no clear solution emerged - but there are some suggestions there you can try.

I'd try removing some packages/configs to pin down what exactly triggered this.  I'd start with nvidia.  You said you installed nvidia and tested x successfully before the problem occurred, but did you reboot after installing nvidia? (i.e. did you ever have a successful boot after installing nvidia?)

Last edited by Trilby (2017-09-28 16:24:17)


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

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#5 2017-09-29 07:09:26

eddilein
Member
From: Germany / Bavaria
Registered: 2008-08-06
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

Hi Forty-Two!

I still don't exactly understand. BUT:

a) I hope the problem still remains
b) you, frustrated, did NOT wipe out the install and destroyed by the way all the gameplay :-)

When I am writing I don't understand, it is my fault.

I am believing you and am convinced the problems are neither wrong nur unrealistic...

Well systemd also cooks with water, as we use to say here in Germany. And to boot with the install media and delete the apropriate link (it is a simple matter of ln -s if I am not completely wrong) who pointend to the lxdm service would have been more ore less the same...

But your way, of course, seems to be even simpler and it is okay!

Trillby is showing us the direction to go:

a) Do you use a HP Laptop?
b) Does it have some kind of Nvidia Graphics?

Have a nice week end, and DON'T RESIGN!

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#6 2017-09-29 08:38:12

forty-two
Member
Registered: 2017-06-30
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

Trilby wrote:

The same problem has been reported before:
https://bbs.archlinux.org/viewtopic.php?id=207880
https://bbs.archlinux.org/viewtopic.php?id=207359
Unfortunately, no clear solution emerged - but there are some suggestions there you can try.

I'd try removing some packages/configs to pin down what exactly triggered this.  I'd start with nvidia.  You said you installed nvidia and tested x successfully before the problem occurred, but did you reboot after installing nvidia? (i.e. did you ever have a successful boot after installing nvidia?)

No, I rebooted all the way down in the steps that I've posted. You'd definitely notice that I was naive enough not to have rebooted right after pacman -Syu, but I don't think it's something that's causing the trouble. My belief is that it's xorg that's causing the problem as all the xorg hooks still get executed (as I can tell from the boot log) before I reach the login prompt. I wish I had rebooted right after the nvidia part and before installing lxde.

By the way, the problem outlined in their posts is exactly the same that I'm having, except the frequency at which ^@ gets printed is much higher making the typing of password, with echo off, impossible. Also, this is a Lenovo laptop (dual booting with windows using systemd-bootctl, although it booted fine enough before I tried the above mentioned things)

Last edited by forty-two (2017-09-29 08:52:31)

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#7 2017-09-29 08:42:22

forty-two
Member
Registered: 2017-06-30
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

eddilein wrote:

Hi Forty-Two!

I still don't exactly understand. BUT:

a) I hope the problem still remains
b) you, frustrated, did NOT wipe out the install and destroyed by the way all the gameplay :-)

When I am writing I don't understand, it is my fault.

I am believing you and am convinced the problems are neither wrong nur unrealistic...

Well systemd also cooks with water, as we use to say here in Germany. And to boot with the install media and delete the apropriate link (it is a simple matter of ln -s if I am not completely wrong) who pointend to the lxdm service would have been more ore less the same...

But your way, of course, seems to be even simpler and it is okay!

Trillby is showing us the direction to go:

a) Do you use a HP Laptop?
b) Does it have some kind of Nvidia Graphics?

Have a nice week end, and DON'T RESIGN!

No, this is a lenovo yoga 500 laptop. Yes, it does have an nvidia graphics card (besides the generic motherboard card). Of course I'm not going to miss the hands on experience of setting up Arch myself, I'll definitely keep on trying different ways. It's just that I've never experienced such a nuisance (all those ^@ s) before....

By the way, what is it that you have not understood? I would be glad to elaborate.

Last edited by forty-two (2017-09-29 08:43:36)

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#8 2017-09-29 08:49:29

loqs
Member
Registered: 2014-03-06
Posts: 17,369

Re: Automatic printing of '^@' after login after installing xorg and lxde.

@forty-two can you install the linux-lts kernel and see if the issue is present under that kernel as well please.

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#9 2017-09-29 08:50:50

eddilein
Member
From: Germany / Bavaria
Registered: 2008-08-06
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

You are not an amateur in the strong sense.

Could your post us something like the /etc/X11/xinit/xinitrc or the content of /etc/X11/xinit/xinitrc.d/ directory?

Yes, it must have something to do with X, because the install media boots fine? (this one has no X!)

I guess we are slowly coming nearer :-)

Edit: Typo

Last edited by eddilein (2017-09-29 08:55:20)

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#10 2017-09-29 08:55:24

forty-two
Member
Registered: 2017-06-30
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

loqs wrote:

@forty-two can you install the linux-lts kernel and see if the issue is present under that kernel as well please.

Sure, let me download it and put them under my esp.... Done!

Last edited by forty-two (2017-09-29 10:55:58)

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#11 2017-09-29 08:56:15

forty-two
Member
Registered: 2017-06-30
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

eddilein wrote:

You are not an amateur in the strong sense.

Could your post us something like the /etc/X11/xinit/xinitrc or the content of /etc/X11/xinit/xinitrc.d/ directory?

Yes, it must have something to do with X, because the install media boots fine? (this one has no X!)

I guess we are slowly coming nearer :-)

Edit: Typo

Definitely, give me some time.... Done!

Last edited by forty-two (2017-09-29 10:55:42)

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#12 2017-09-29 09:00:34

loqs
Member
Registered: 2014-03-06
Posts: 17,369

Re: Automatic printing of '^@' after login after installing xorg and lxde.

forty-two wrote:
loqs wrote:

@forty-two can you install the linux-lts kernel and see if the issue is present under that kernel as well please.

Sure, let me download it and put them under my esp....

You should just be able to install it under arch-chroot and if /boot is the systems ESP the kernel and initrd will be placed on the ESP correctly.
You may still have to make a boot entry for the new kernel depending on which boot loader/manager you use.

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#13 2017-09-29 10:42:32

forty-two
Member
Registered: 2017-06-30
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

loqs wrote:

You should just be able to install it under arch-chroot and if /boot is the systems ESP the kernel and initrd will be placed on the ESP correctly.
You may still have to make a boot entry for the new kernel depending on which boot loader/manager you use.

Yeah, thanks. I installed linux-lts and made the subsequent adding of -lts in the loader.conf entries. System boots exactly the same with the lts kernel (sure, because I have removed the generic linux kernel) but the problem of ^@ is still there.

Last edited by forty-two (2017-09-29 10:59:39)

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#14 2017-09-29 10:54:58

forty-two
Member
Registered: 2017-06-30
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

Output of pacman -Q (highlighted possible faulty ones):
https://pastebin.com/z967RMEE

Contents of /etc/X11/xinit/xserverrc :

#!/bin/sh
exec /usr/bin/X -nolisten tcp "$@"

Contents of /etc/X11/xinit/xinitrc :

#!/bin/sh

userresources=$HOME/.Xresources
usermodmap=$HOME/.Xmodmap
sysresources=/etc/X11/xinit/.Xresources
sysmodmap=/etc/X11/xinit/.Xmodmap

# merge in defaults and keymaps

if [ -f $sysresources ]; then







    xrdb -merge $sysresources

fi

if [ -f $sysmodmap ]; then
    xmodmap $sysmodmap
fi

if [ -f "$userresources" ]; then







    xrdb -merge "$userresources"

fi
if [ -f "$usermodmap" ]; then
    xmodmap "$usermodmap"
fi

# start some nice programs

if [ -d /etc/X11/xinit/xinitrc.d ] ; then
 for f in /etc/X11/xinit/xinitrc.d/?*.sh ; do
  [ -x "$f" ] && . "$f"
 done
 unset f
fi

twm &
xclock -geometry 50x50-1+1 &
xterm -geometry 80x50+494+51 &
xterm -geometry 80x20+494-0 &
exec xterm -geometry 80x66+0+0 -name login

Contents of /etc/X11/xinit/xinit.d/50-systemd-user.sh :

#!/bin/sh

systemctl --user import-environment DISPLAY XAUTHORITY

if which dbus-update-activation-environment >/dev/null 2>&1; then
        dbus-update-activation-environment DISPLAY XAUTHORITY
fi

Last edited by forty-two (2017-09-29 11:09:21)

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#15 2017-09-29 10:59:01

Trilby
Inspector Parrot
Registered: 2011-11-29
Posts: 29,525
Website

Re: Automatic printing of '^@' after login after installing xorg and lxde.

forty-two please edit your post to use code tags rather than color tags.  Code tags are displayed as monospaced fonts in a scrollable textarea, color is not.  Further the colors you chose are *very* hard to read on some forum themes.

forty-two wrote:

/etc/X11/xinit/xserverrc (highly suspicious as being the culprit due to the @ symbol)

No, that's a normal bash parameter variable.

The '^@' is not two characters ^ and @ but is the representation of a NULL byte.  Your system thinks it is receiving a series of null bytes from the keyboard.

Last edited by Trilby (2017-09-29 11:10:36)


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

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#16 2017-09-29 11:00:40

forty-two
Member
Registered: 2017-06-30
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

Trilby wrote:

forty-two please edit your post to use code tags rather than color tags.  Code tags are displayed as monospaced fonts in a scrollable textarea, color is not.  Further the colors you chose are *very* hard to read on some forum themes.

forty-two wrote:

/etc/X11/xinit/xserverrc (highly suspicious as being the culprit due to the @ symbol)

No, that's a normal bash parameter variable.

Sorry, I hope the formatting is fine now. Also, please excuse me, I don't have a lot of experience with linux. In fact, this my first linux installation. :-)

Last edited by forty-two (2017-09-29 11:12:37)

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#17 2017-09-29 11:13:34

eddilein
Member
From: Germany / Bavaria
Registered: 2008-08-06
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

Okay, thanks!

At least it is getting nicer:

May I compare your /etc/X11/xinit/xinitrc with mine?

Mine is much simpler:

#!/bin/sh


userresources=$HOME/.Xresources
usermodmap=$HOME/.Xmodmap
sysresources=/etc/X11/xinit/.Xresources
sysmodmap=/etc/X11/xinit/.Xmodmap

# merge in defaults and keymaps

if [ -f $sysresources ]; then

    xrdb -merge $sysresources

fi

if [ -f $sysmodmap ]; then
    xmodmap $sysmodmap
fi

if [ -f "$userresources" ]; then

    xrdb -merge "$userresources"

fi

if [ -f "$usermodmap" ]; then
    xmodmap "$usermodmap"
fi

# start some nice programs

if [ -d /etc/X11/xinit/xinitrc.d ] ; then
 for f in /etc/X11/xinit/xinitrc.d/?*.sh ; do
  [ -x "$f" ] && . "$f"
 done
 unset f
fi

twm &
xclock -geometry 50x50-1+1 &
xterm -geometry 80x50+494+51 &
xterm -geometry 80x20+494-0 &
exec xterm -geometry 80x66+0+0 -name login

I must remark: It is deliberately as simple as possible, and, for example, my own keyboard setting are inititiated with loadkeys de-latin1 in a simple bash script.

Anyhow, I know you are not dumb, ant the 1st part of the following line is superfluous:

Please make a little backup of the files in question, and try mine...

I guess the "underscripts" in the /etc/X11/xinit/xinitrc.d/ folder are not sooo important, but that would be my next next step, if it still does'nt go forward.

And, nice from you to play the game till the end!

Edit:

It is double nice because my script is based on LXDE, too...

Edit II:

And mine is working...

Edit III

How did you do that, with the code? me too...

I will read this post again! :-)

Edit IV

Ah, the brackets :-)

Last edited by eddilein (2017-09-29 11:27:20)

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#18 2017-09-29 11:14:19

forty-two
Member
Registered: 2017-06-30
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

Trilby wrote:

The '^@' is not two characters ^ and @ but is the representation of a NULL byte.  Your system thinks it is receiving a series of null bytes from the keyboard.

Thanks, but I know at least that.

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#19 2017-09-29 11:21:03

Trilby
Inspector Parrot
Registered: 2011-11-29
Posts: 29,525
Website

Re: Automatic printing of '^@' after login after installing xorg and lxde.

eddilein, please also use code tags.

Also xinitrc files are completely irrelevant for the login problem.  They may be relevant for the other symptom mentioned in the first post of the nonresponsive X session, but this thread should stick with the one problem of loggin in.


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

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#20 2017-09-29 11:25:13

forty-two
Member
Registered: 2017-06-30
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

eddilein wrote:

Okay, thanks!

At least it is getting nicer:

May I compare your /etc/X11/xinit/xinitrc with mine?

Mine is much simpler:

#!/bin/sh

userresources=$HOME/.Xresources
usermodmap=$HOME/.Xmodmap
sysresources=/etc/X11/xinit/.Xresources
sysmodmap=/etc/X11/xinit/.Xmodmap

# merge in defaults and keymaps

if [ -f $sysresources ]; then

    xrdb -merge $sysresources

fi

if [ -f $sysmodmap ]; then
    xmodmap $sysmodmap
fi

if [ -f "$userresources" ]; then

    xrdb -merge "$userresources"

fi

if [ -f "$usermodmap" ]; then
    xmodmap "$usermodmap"
fi

# start some nice programs

if [ -d /etc/X11/xinit/xinitrc.d ] ; then
for f in /etc/X11/xinit/xinitrc.d/?*.sh ; do
  [ -x "$f" ] && . "$f"
done
unset f
fi

twm &
xclock -geometry 50x50-1+1 &
xterm -geometry 80x50+494+51 &
xterm -geometry 80x20+494-0 &
exec xterm -geometry 80x66+0+0 -name login

I must remark: It is deliberately as simple as possible, and, for example, my own keyboard setting are inititiated with loadkeys de-latin1 in a simple bash script.

Anyhow, I know you are not dumb, ant the 1st part of the following line is superfluous:

Please make a little backup of the files in question, and try mine...

I guess the "underscripts" in the /etc/X11/xinit/xinitrc.d/ folder are not sooo important, but that would be my next next step, if it still does'nt go forward.

And, nice from you to play the game till the end!

Edit:

It is double nice because my script is based on LXDE, too...

Ummm.... apart from the useless blank lines in mine, I see no difference between your one and mine.
I think systemd-boot could be worth looking at, if X is bothered by it in any way. Note that my installation of systemd-boot was done when my esp was mounted, but I was not in chroot. As a result, I had to manually create loader.conf and arch.conf (and I still have to push the vmlinuz and initramfs files to esp/boot/Arch manually after each update). Read more here: https://bbs.archlinux.org/viewtopic.php?id=227810

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#21 2017-09-29 11:28:46

forty-two
Member
Registered: 2017-06-30
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

Any suggestions on what things I might try uninstalling (nvidia ??) so that I can at least log in normally? Thanks for everyone's help so far....

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#22 2017-09-29 11:29:35

eddilein
Member
From: Germany / Bavaria
Registered: 2008-08-06
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

Well?

twm is surely not my windows manager...

So maybe we are wrong...

Edit:

... and, sorry for the brackets, but YOU began!

Bye!

Last edited by eddilein (2017-09-29 11:36:14)

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#23 2017-09-29 11:30:19

forty-two
Member
Registered: 2017-06-30
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

Trilby wrote:

The same problem has been reported before:
https://bbs.archlinux.org/viewtopic.php?id=207880
https://bbs.archlinux.org/viewtopic.php?id=207359
Unfortunately, no clear solution emerged - but there are some suggestions there you can try.

I'd try removing some packages/configs to pin down what exactly triggered this.  I'd start with nvidia.  You said you installed nvidia and tested x successfully before the problem occurred, but did you reboot after installing nvidia? (i.e. did you ever have a successful boot after installing nvidia?)

Trying with removing nvidia...

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#24 2017-09-29 11:30:50

Trilby
Inspector Parrot
Registered: 2011-11-29
Posts: 29,525
Website

Re: Automatic printing of '^@' after login after installing xorg and lxde.

forty-two wrote:

Any suggestions on what things I might try uninstalling (nvidia ??)

That's been my suggestion from the start.

I don't see anything obvious in your package list, but if you installed any network and/or wireless drivers those might be candidates too.  Otherwise I don't see anything that should interact with the kernel at a low-enough / early-enough level to cause these symptoms.

However, it might also be worth considering enabled services.  ``systemctl list-units`` output could be a good next step if nvidia doesn't pan out as a suspect.

Last edited by Trilby (2017-09-29 11:36:44)


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

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#25 2017-09-29 11:46:08

eddilein
Member
From: Germany / Bavaria
Registered: 2008-08-06
Posts: 21

Re: Automatic printing of '^@' after login after installing xorg and lxde.

Yeah Trilby, you are right.

I don't use nvidia but i would kindly suggest something like "sudo pacman -Rs nvidia" or similar...

That is really getting interesting.

Please forty-two (also my prefered number, not only yours... from the Galaxy) keep us informed!

Nice!

Edit:

I did, so mesa?

stay tenacious!

Last edited by eddilein (2017-09-29 11:56:50)

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