Article 5N2T9 weird X keyboard issue started today

weird X keyboard issue started today

by
Skaperen
from LinuxQuestions.org on (#5N2T9)
a weird keyboard issue started today. after doing certain things like GNU emacs or things that run GNU readline for input and they exit back to the shell, the keyboard is unusable for a few seconds. digging into this i find:

1. when it happens it affects every window in every workspace in this X windows server but it does not affect other X windows servers. i run emacs followed by a 2nd command on the same line to switch workspace or switch user (a different X server). the next workspace has the problem but the next user does not. so this tells me it must be an X issue triggered by the software i ran and not a kernel issue. i have many (about 20) users concurrently logged in on separate X servers (yes, 20 X servers) each of which is running XFCE 4.12 and has 10 workspaces (yes, 200 workspaces system wide).

2. after running the software, my typing seems to not work for a period of time that varies from about 3 seconds to as long as 15 seconds. this is not literally measured. i am estimating the time. after exploring this for a while, it seems that what is happening is as if the Ctrl key is being held down. pressing letter c gets ^C during this time. if i actually press Ctrl and something like c, it still does the Ctrl thing. releasing Ctrl does not restore anything. it is as if there is another Ctrl flag in the key press parsing logic. pressing Enter works. the command "reset" was tried but it has no effect.

3. i uninstalled emacs and installed emacs-nox. it still triggers the issue. i rebooted (even powered off and back on) and this problem still happens. it happens on other users (other X servers) as well.

4. i have just discovered (before submitting this as a new thread) that even "cat >/dev/null" will trigger the issue. so it is not a emacs/readline issue. it may be a bash issue. it may have something to do with read operations but during these programs i'm not seeing the issue. that's what makes me think that bash may be triggering it.

this is a very new problem and i really don't know what keywords to search for. i have guessed a few words and searched on qwant, duckduckgo, and google, but have found nothing like this.

any ideas? any suggestions on things to try to narrow this down? any good keywords to search for especially given that many people will see a broader issue?

i've intended to switch to emacs-nox for a couple years. got that done, today.latest?d=yIl2AUoC8zA latest?i=3CDVL6hCm-c:uHJQX5IHZko:F7zBnMy latest?i=3CDVL6hCm-c:uHJQX5IHZko:V_sGLiP latest?d=qj6IDK7rITs latest?i=3CDVL6hCm-c:uHJQX5IHZko:gIN9vFw3CDVL6hCm-c
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