Thinkpad X60s Volume Keys under Linux

While trying out MX Linux 19 Beta on my old Thinkpad X60s I saw that the volume keys did work but don’t show up as OSD. After googling a bit I found Thinkpad-Wiki which suggests writing echo 0x00fc7fff > /sys/devices/platform/thinkpad_acpi/hotkey_mask into /etc/rc.local before exit 0 and reboot. That solved it! Thanks.