Hi, On Mon, Oct 11, 2021 at 12:16 AM Ryan McClue <[email protected]> wrote: > > PROBLEM: > I'm on a fresh install of Ubuntu 20.04 (xorg 1.20.11), with 2 connected > keyboards (built-in and USB). > When I hit keys on each keyboard simultaneously in a program like firefox, > gnome-terminal etc. stalling/lag occurs. > It only happens for keyboards it seems as moving an external mouse and > trackpad together causes no issues. > > TO REPRODUCE: > To investigate the problem I wrote a simple C file (see attached > 'xorg-lag.c', compile with $(gcc xorg-lag.c -o xorg-lag)) > The program finds keyboard devices under /dev/input/event and uses epoll to > poll them for input via the evdev interface. > > If I start entering keys on one keyboard and then switch to the other, the > program stalls briefly. > If I simultaneously enter keys on each keyboard the program stalls > indefinitely until I stop entering keys. > I have tested with different keyboards and experience the same result. > If I switch to a virtual terminal and run I experience no lag. > This makes me think it is a bug with xorg.
It sounds like you mean https://gitlab.gnome.org/GNOME/mutter/-/issues/398 (although https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/1858 has more recent context). I don't think there's a single culprit here, and they're likely just indirectly relevant in this mailing list. Cheers, Carlos
