This script allows toggling ASPM at runtime per bus via raw PCI config writes.
Example for Snapdragon X series:
doas enable-aspm.sh 0006:00:00.0 0006:01:00.0 0 # SSD ASPM OFF
doas enable-aspm.sh 0006:00:00.0 0006:01:00.0 2 # SSD ASPM ON
doas enable-aspm.sh 0004:00:00.0 0004:01:00.0 0 # WiFi ASPM OFF
doas enable-aspm.sh 0004:00:00.0 0004:01:00.0 2 # WiFi ASPM ON