There is no "capslock LED key event". 0xfa is KBD_REPLY_ACK, and the
device queues it in response to guest port writes. Yes, the ack can
race with actual key events. But IMO that isn't a bug in qemu.
Probably the linux kernel just throws away everything until it got the
ack for the port write,
### Reproduce steps
Add `fprintf(stderr, "ps2_queue 0x%x\n", b);` to `hw/input/ps2.c` and
re-build qemu.
- qemu-system-x86_64 -hda --enable-kvm -m <> -display vnc=:1
- vncviewer -Shared :5901
In guest os, find the keyboard device(very likely to be /dev/input/event0)
```
sudo evtest
