[LAU] Unbinding USB devices

[Ralf Mardorf]

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 at 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 at archlinux ~]$ cd /sys/bus/pci/drivers/ehci-pci/
[rocketmouse at 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 at archlinux ehci-pci]$ printf "0000:00:1a.0" | sudo tee unbind >/dev/null
[sudo] password for rocketmouse: 
[rocketmouse at 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 at 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