Qubes sometimes repeats keyboard keys on lag spikes

[Atrate]

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Qubes OS release

4.2.3, also seen on 4.1.x.

Reproduced on three different hardware configurations, both with btrfs and lvm-thin pools, with both integrated (laptop) keyboards and USB keyboards.

Brief summary

Qubes sometimes repeats keyboard keys on lag spikes (usually caused by high I/O, like shutting down/starting many VMs at the same time). The degree to which the keys are repeated varies from 1 time to many times. Reducing those lag spikes (with async discard on btrfs) reduced the occurence of the problem significantly, but not completely.

Steps to reproduce

Perform some I/O intensive tasks, like starting/shutting many VMs down at the same time while typing in a normal way in some other VM. Some keys will get repeated on lag spikes, like thiiiiiiiiiis.

Expected behavior

No key repeat.

Actual behavior

Sometimes awwwwwwwwwwwwwkward when I send a messsssssssssage.

Related issues

Possibly #8636

[andrewdavidwong]

I've experienced this too. It's especially severe when backing up to an external hard drive.