id = 2948
title = "-display sdl causes mice with relative movement to read garbage offsets"
state = "opened"
created_at = "2025-05-05T17:34:44.318Z"
closed_at = "n/a"
labels = []
url = "https://gitlab.com/qemu-project/qemu/-/issues/2948"
host-os = "Arch Linux"
host-arch = "x86_64"
qemu-version = "10.0.0"
guest-os = "Arch Linux"
guest-arch = "x86_64"
description = """`-device virtio-mouse` and `-device usb-mouse` (and probably other mice which send relative mouse movement data) are behaving incorrectly under linux guest and jitter a lot. In this specific case it only seems to happen with `-display sdl` as I could not reproduce this same issue with other of the following configurations: `-display gtk` and `-display spice-app` running with virt-viewer.
This behavior is not present when running a Windows guest with the same configuration using `-display sdl`

Another weird side note: this behavior is less apparent when running `evtest` on the exact mouse device having issues.

![Video_2025-05-05_20-11-56](/uploads/589d74106d2e9bb5713234de451f5326/Video_2025-05-05_20-11-56.mp4)"""
reproduce = """1. Install guest operating system
2. Install gnome metapackage and enable GDM
3. Reboot
4. The mouse shows jittery motion on the GDM screen."""
additional = "n/a"