[Arch] How to reduce tty device number?

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[Arch] How to reduce tty device number?

Unread postby Moricio78 » Sat Aug 29, 2015 3:50 pm

Hello,

On my Archlinux I have 320 /dev/tty* (0 to yzf).
And so much sys-devices-virtual-tty-tty*.device (loaded active plugged) in systemctl.

I can't find the file where this number is set.

I tried with NAutoVTs=6 in /etc/systemd/logind.conf but no changes.
Have you an idea?

Thanks
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Re: [Arch] How to reduce tty device number?

Unread postby odroid » Sat Aug 29, 2015 7:11 pm

I think you would better post the question on ALARM forum.
http://archlinuxarm.org/forum/
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Re: [Arch] How to reduce tty device number?

Unread postby gripped » Sat Aug 29, 2015 10:32 pm

I think it is kernel related

https://raw.githubusercontent.com/hardk ... _defconfig
Code: Select all
CONFIG_LEGACY_PTYS=y
CONFIG_LEGACY_PTY_COUNT=256

(it is also set in the u2 kernel)

On my Desktop Intel Arch CONFIG_LEGACY_PTYS is not set

Code: Select all
ls -l /dev/tty* | wc -l
69


On odroid XU3
Code: Select all
ls -1 /dev/tty* | wc -l
329


329-69-4(the four /dev/ttySAC*)=256

So if they really bother you I think you have to compile the kernel with CONFIG_LEGACY_PTYS is not set.

As always I could be wrong ;)
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Re: [Arch] How to reduce tty device number?

Unread postby Moricio78 » Mon Aug 31, 2015 2:50 pm

I was afraid to this answer.
Thank you for information, I will try to compile a new kernel.
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Re: [Arch] How to reduce tty device number?

Unread postby Moricio78 » Wed Sep 02, 2015 5:38 pm

Finally I used the following commands in u-boot and it works
setenv mmcargs 'setenv bootargs ...... pty.legacy_count=2'
saveenv

Now I am 65 tty.
It's better but I do not understand why 65.
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Re: [Arch] How to reduce tty device number?

Unread postby NC-Tony-Casanova » Thu Aug 09, 2018 10:19 am

Has anyone figured out how to reduce the number of ttys on ODROID?

76 ttys on UBUNTU

ls -l /dev/tty* | wc -l
76


This is not just ARCH.

lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.5 LTS
Release: 16.04
Codename: xenial


cat /etc/*release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04.5 LTS"
NAME="Ubuntu"
VERSION="16.04.5 LTS (Xenial Xerus)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 16.04.5 LTS"
VERSION_ID="16.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
VERSION_CODENAME=xenial
UBUNTU_CODENAME=xenial
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Re: [Arch] How to reduce tty device number?

Unread postby tobetter » Sat Aug 11, 2018 1:02 am

NC-Tony-Casanova wrote:Has anyone figured out how to reduce the number of ttys on ODROID?

76 ttys on UBUNTU

ls -l /dev/tty* | wc -l
76


This is not just ARCH.

lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.5 LTS
Release: 16.04
Codename: xenial


cat /etc/*release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04.5 LTS"
NAME="Ubuntu"
VERSION="16.04.5 LTS (Xenial Xerus)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 16.04.5 LTS"
VERSION_ID="16.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
VERSION_CODENAME=xenial
UBUNTU_CODENAME=xenial

You would be able to reduce the number of virtual consoles /dev/tty[0-63] after recompiling the kernel if you change MAX_NR_CONSOLES to other number you'd like to.
Code: Select all
  6 /*
  7  * These constants are also useful for user-level apps (e.g., VC
  8  * resizing).
  9  */
 10 #define MIN_NR_CONSOLES 1       /* must be at least 1 */
 11 #define MAX_NR_CONSOLES 63      /* serial lines start at 64 */
 12                 /* Note: the ioctl VT_GETSTATE does not work for
 13                    consoles 16 and higher (since it returns a short) */
 14
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Re: [Arch] How to reduce tty device number?

Unread postby NC-Tony-Casanova » Tue Aug 14, 2018 1:54 pm

Thank you. I will give it a try.
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