[LAU] Unbinding USB devices

Hi, I've got a new mobo, it's a GIGABYTE GA-B85M-D3H. It has got 8 "USB 2.0/1.1 ports"[1] and 2 "USB 3.0/2.0 ports"[1]. [1] Quoting the user's manual Actually it provides 4 USB 3.0/2.0 ports, but only 2 are available at the moment, since I don't have brackets/front panels for USB 3.0. There are two ehci devices, one shares the IRQ with audio cards. If I unbind the ehci device that shares the IRQ with audio cards, still all 10 available USB ports work, but I get rid of sharing the IRQ with USB. Could somebody explain what this does mean? If I unbound ports on my old mobo, they stopped working. [rocketmouse@archlinux ~]$ rtirq status PID CLS RTPRIO NI PRI %CPU STAT COMMAND 102 FF 90 - 130 0.0 S irq/16-ehci_hcd 225 FF 90 - 130 0.0 S irq/27-xhci_hcd 119 FF 89 - 129 0.0 S irq/23-ehci_hcd 312 FF 85 - 125 0.0 S irq/16-snd_hdsp 313 FF 80 - 120 0.0 S irq/16-snd_ice1 38 FF 50 - 90 0.0 S irq/9-acpi 52 FF 50 - 90 0.0 S irq/8-rtc0 101 FF 50 - 90 0.0 S irq/1-i8042 104 FF 50 - 90 0.4 S irq/25-ahci[000 224 FF 50 - 90 0.0 S irq/26-mei_me 227 FF 50 - 90 0.0 S irq/5-parport0 229 FF 50 - 90 0.0 S irq/28-snd_hda_ 235 FF 50 - 90 0.0 S irq/30-i915 314 FF 50 - 90 0.0 S irq/18-i801_smb 315 FF 50 - 90 0.0 S irq/31-snd_hda_ 442 FF 50 - 90 0.0 S irq/29-enp3s0 3 TS - 0 19 0.0 S ksoftirqd/0 21 TS - 0 19 0.0 S ksoftirqd/1 [rocketmouse@archlinux ~]$ cd /sys/bus/pci/drivers/ehci-pci/ [rocketmouse@archlinux ehci-pci]$ ls -l | grep devices lrwxrwxrwx 1 root root 0 Feb 19 17:00 0000:00:1a.0 -> ../../../../devices/pci0000:00/0000:00:1a.0 lrwxrwxrwx 1 root root 0 Feb 19 17:00 0000:00:1d.0 -> ../../../../devices/pci0000:00/0000:00:1d.0 [rocketmouse@archlinux ehci-pci]$ printf "0000:00:1a.0" | sudo tee unbind >/dev/null [sudo] password for rocketmouse: [rocketmouse@archlinux ehci-pci]$ ls -l | grep devices lrwxrwxrwx 1 root root 0 Feb 19 17:00 0000:00:1d.0 -> ../../../../devices/pci0000:00/0000:00:1d.0 [rocketmouse@archlinux ehci-pci]$ rtirq status PID CLS RTPRIO NI PRI %CPU STAT COMMAND 225 FF 90 - 130 0.0 S irq/27-xhci_hcd 119 FF 89 - 129 0.0 S irq/23-ehci_hcd 312 FF 85 - 125 0.0 S irq/16-snd_hdsp 313 FF 80 - 120 0.0 S irq/16-snd_ice1 38 FF 50 - 90 0.0 S irq/9-acpi 52 FF 50 - 90 0.0 S irq/8-rtc0 101 FF 50 - 90 0.0 S irq/1-i8042 104 FF 50 - 90 0.1 S irq/25-ahci[000 224 FF 50 - 90 0.0 S irq/26-mei_me 227 FF 50 - 90 0.0 S irq/5-parport0 229 FF 50 - 90 0.0 S irq/28-snd_hda_ 235 FF 50 - 90 0.0 S irq/30-i915 314 FF 50 - 90 0.0 S irq/18-i801_smb 315 FF 50 - 90 0.0 S irq/31-snd_hda_ 442 FF 50 - 90 0.0 S irq/29-enp3s0 3 TS - 0 19 0.0 S ksoftirqd/0 21 TS - 0 19 0.0 S ksoftirqd/1 Regards, Ralf