diff --git a/rules.d/60-persistent-input.rules b/rules.d/60-persistent-input.rules
index 7ac43a8074..95037f88c6 100644
--- a/rules.d/60-persistent-input.rules
+++ b/rules.d/60-persistent-input.rules
@@ -5,20 +5,24 @@ SUBSYSTEM!="input", GOTO="persistent_input_end"
 SUBSYSTEMS=="bluetooth", ENV{ID_BUS}="bluetooth", GOTO="persistent_input_end"
 # Bluetooth devices don't always have the bluetooth subsystem
 ATTRS{id/bustype}=="0005", ENV{ID_BUS}="bluetooth", GOTO="persistent_input_end"
-SUBSYSTEMS=="acpi", ENV{ID_BUS}="acpi"
-# platform must be before serio as serio can be child
-SUBSYSTEMS=="platform", ENV{ID_BUS}="platform"
+
+# we have to assign the most specific bus, so first check for leaf buses
 SUBSYSTEMS=="i2c", ENV{ID_BUS}="i2c"
 SUBSYSTEMS=="rmi4", ENV{ID_BUS}="rmi"
 SUBSYSTEMS=="serio", ENV{ID_BUS}="i8042"
 SUBSYSTEMS=="spi", ENV{ID_BUS}="spi"
 
+# then only assign something less specific if ID_BUS was not set yet..
+# usb has middle specificity (e.g. could have an i2c bridge on it, but is under acpi/pci/platform)
 SUBSYSTEMS=="usb", ENV{ID_BUS}=="", IMPORT{builtin}="usb_id"
 
-# subsystems before (usb, platform, i2c) can be under pci so only set them if we still have no ID_BUS.
-# we could set this the first but will break the ENV{ID_BUS}=="" condition for usb.
+# pci is usually below acpi/platform
 SUBSYSTEMS=="pci", ENV{ID_BUS}=="", ENV{ID_BUS}="pci"
 
+# finally, these are the root buses
+SUBSYSTEMS=="acpi", ENV{ID_BUS}=="", ENV{ID_BUS}="acpi"
+SUBSYSTEMS=="platform", ENV{ID_BUS}=="", ENV{ID_BUS}="platform"
+
 # determine class name for persistent symlinks
 ENV{ID_INPUT_KEYBOARD}=="?*", ENV{.INPUT_CLASS}="kbd"
 ENV{ID_INPUT_MOUSE}=="?*", ENV{.INPUT_CLASS}="mouse"