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rubik

Member

Registered: 2012-03-23

Posts: 104

Random delays when typing in a terminal like xterm or rxvt-unicode

When I'm typing in a terminal, I observe a frequent random delay that causes the terminal interface not to update for a second, or in some cases it just doesn't update at all until the next keystroke.

Example: I write "test" and the terminal displays "tes". If I press space (or any other keystroke, for that matter, like backspace), the terminal updates to "test " (and if I had pressed a backspace it would show "tes", correctly). Sometimes, this also happens with commands output. E.g. I execute "ls" and nothing shows. If I press something, the terminal updates and shows the output and the new character in a new prompt.

Actually, this also happens in full-fledged GUIs like a browser. However, those cases are pretty rare.

I'm not sure where I should start investigating, so any help would be appreciated. This is a Lenovo Thinkpad x390. I have the same exact urxvt configuration on two other computers, so that shouldn't be the culprit. Maybe it's a keyboard/video driver issue?

$ uname -a
Linux miki-laptop 5.6.15-arch1-1 #1 SMP PREEMPT Wed, 27 May 2020 23:42:26 +0000 x86_64 GNU/Linux

Last edited by rubik (2020-06-07 15:05:09)

seth

Member

Registered: 2012-09-03

Posts: 64,943

Re: Random delays when typing in a terminal like xterm or rxvt-unicode

If you (or your WM ;-) uses any compositor, get that out of the equation at first.
Also try to figure whether this is something visual or the input is indeed processed on a delay, eg. "printf '\a'" will trigger the terminal bell (the audio being detached from any visual delays)

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rubik

Member

Registered: 2012-03-23

Posts: 104

Re: Random delays when typing in a terminal like xterm or rxvt-unicode

Thanks seth. The \a character doesn't make any sound. I guess it's because I have disabled bios beeps. I will enable that and try again.

I don't use a compositor, so that makes things easier. I run X + bspwm. I have made some progress and found that the problem disappears if I run "xset -r" to disable Xorg auto-repeat. So it looks like the issue is at the X level. However, I would like to use auto-repeat. I will experiment with the typematic settings as  described here:
https://wiki.archlinux.org/index.php/Xo … y_and_rate