Arch Linux

vodun

Member

Registered: 2020-07-02

Posts: 3

[SOLVED] Input lag in terminal.

I have this issue which appeared maybe 2 or 4 months ago where basically the terminal doesn't print the character I have just typed. It occurs randomly and I would say quite frequently like every 3-5 seconds. As soon as I type another character it's going to display the previous one.

So basically if I type: "this is an example", It might just display "this is an e", hiding the "x" and will only display it when I type the "a".

It feels like the keyboard is sticky or something which is a bit annoying so I have tried to solve the issue but wasn't successful.

I am using i3, uxrvt and my video driver is intel, here's what I tried:

• Replaced the modesetting driver with xf86-video-intel. Used UXA instead of SNA.

• Installed fluxbox + xterm

• Disabled/Enabled Framebuffer compression (i915.enable_fbc)

• Removed all my configuration in .Xresources (urxvt config + font)

• Removed all my i3status configuration

I found several related issues (from years ago though) but lot of them mention a compositor that I don't use.

Now this issue only occurs in the terminal, meaning any GUI application or TTY console are not impacted.

Any idea where does this come from?

Last edited by vodun (2020-07-02 12:44:47)

Ropid

Member

Registered: 2015-03-09

Posts: 1,069

Re: [SOLVED] Input lag in terminal.

You are not using any compositor?

vodun

Member

Registered: 2020-07-02

Posts: 3

Re: [SOLVED] Input lag in terminal.

No, I am not as this is not included in i3wm and never had any issue without it.

Ropid

Member

Registered: 2015-03-09

Posts: 1,069

Re: [SOLVED] Input lag in terminal.

Your problem is really confusing. I can't come up with any idea that fits with everything you mention. Everything I can come up with gets disproven by one of the things you already tried.

If this is caused by the graphics driver, maybe a different kernel version behaves different? If you currently use the normal "linux" package, you could try the "linux-lts" package to see if kernel 5.4 doesn't have the problem.

Because I can't come up with a good idea, I would concentrate on the fact that this issue wasn't there a few months ago. This command line here filters the pacman log to just the lines about package changes:

grep -E '\] (ins|upg|rem)\w+ ' /var/log/pacman.log | less +G

If you try browsing around the date where the problem could have started, maybe you can guess what package change caused this.

There's also a special Arch mirror server named "Arch Linux Archive" that has old packages. You can use that mirror to sort-of travel back through time to how Arch was like at certain dates. If you can find the exact day where the problem first showed up, this should be helpful in fixing the problem. How to use that archive mirror is explained here:

https://wiki.archlinux.org/index.php/Arch_Linux_Archive

Check out section "3.2 How to restore all packages to a specific date" and look at the mirrorlist example file there.

You will need to use "pacman -Syuu" with two "-u" to update, without the second "-u", pacman will refuse to install old packages.

Last edited by Ropid (2020-07-02 11:27:11)

vodun

Member

Registered: 2020-07-02

Posts: 3

Re: [SOLVED] Input lag in terminal.

Thanks for the suggestions Ropid. I have installed the linux-lts kernel and it looks good.

I have tried other versions as well and it seems that the 5.5 release introduced the issue.

Did a quick search on the kernel bugzilla but didn't find something conclusive and I am not sure what to look for anyway.

I guess the next step would be to bisect the kernel between 5.4.49 and 5.5 and find the offending commit.

I am putting this as SOLVED since installing linux-lts does fix the issue and I will come back later to this post when I have more details.

Thanks again