@jkozee @Tom-Elliott Sorry for bringing up such an old topic again. Working on moving towards the new 5.10.x kernel I was looking at the patches we still apply to our kernel. Most are part of the upstream kernel but not the fix discussed in this topic.
Though the kernel code has changed a bit and I am wondering if we’d still see the slowness without our fix? Would anyone of you be able to replicate the issue with a 5.10.x kernel (with and without fix)?
Searching the web a little more I stumbled upon this patch that made it into the official kernel not long ago: https://patchwork.kernel.org/project/linux-input/patch/20200910143455.109293-12-boqun.feng@gmail.com/
Not sure but could play a role in this case. Anyway it would be great to see if the issue can still be replicated with the newer kernel - without fix.