Same Problem Dell XPS 15z Kernel: 4.18.0-22-generic OS: 18.04.02 Window manager: KDE Not using Nvidia blob drivers.
Editing grub with "acpi=force reboot=pci" didn't help.
Sometimes also partially freezes when using firefox (mouse dosen't move, ping command dosen't work, can't kill -9 firefox process)
Same Problem Dell XPS 15z
Kernel: 4.18.0-22-generic
OS: 18.04.02
Window manager: KDE
Not using Nvidia blob drivers.
Editing grub with "acpi=force reboot=pci" didn't help.
Sometimes also partially freezes when using firefox (mouse dosen't move, ping command dosen't work, can't kill -9 firefox process)