More information: I am starting QEMU like this:
qemu-system-x86_64 \ -m 8G -hda hda.img -cpu host -accel kvm -smp 8 \ -vga virtio -display gtk,gl=on,show-cursor=on \ -usb -device usb-tablet \ -audiodev id=pa,driver=pa,in.frequency=44100,out.frequency=44100 \ -device intel-hda -device hda-duplex,audiodev=paThe host is running Bullseye (previously testing), configured with amdgpu (OpenGL 4.6) and PipeWire.