[Unit]
Description=Setup special irq affinity
Before=sysinit.target
After=local-fs.target
DefaultDependencies=no

[Service]
Type=oneshot
ExecStart=/bin/true
ExecStartPost=-/bin/sh -c 'for i in `cat /proc/interrupts | grep usb | cut -d ":" -f 1`; do echo "4-7" > /proc/irq/$i/smp_affinity_list; done'

[Install]
WantedBy=sysinit.target