[LAU] Something interesting about kernel 3.6.5-rt14

[Jeremy Jongepier]

On 11/03/2012 10:05 PM, Ralf Mardorf wrote:
> On Sat, 3 Nov 2012 08:43:11 -0700
> "Len Ovens" <len at ovenwerks.net> wrote:
>
>> Playing with PCI_latency made things worse for me, no gain and an
>> unstable machine. This will have no effect whatever on PCIe cards.
>
> Okay, so I only will unbind 2 USB ports. FWIW some things need to be
> done in a different way, than it's described by "linuxmusicians" and
> stopping networking does cause trouble. I couldn't find out how to
> unbind the 2 USB ports.
>

Now you've got:

echo -n "0000:00/0000:00:13.2" > /sys/bus/pci/drivers/ohci_hcd/unbind
echo -n "0000:00/0000:00:13.4" > /sys/bus/pci/drivers/ohci_hcd/unbind

Which yields:

 > tuning: line 28: echo: write error: No such device
 > tuning: line 29: echo: write error: No such device

Maybe you could try:

echo -n "0000:00:13.2" > /sys/bus/pci/drivers/ohci_hcd/unbind
echo -n "0000:00:13.4" > /sys/bus/pci/drivers/ohci_hcd/unbind

You should also check which driver the USB ports are using, ohci, ehci 
or uhci. You can check this with cat /proc/interrupts | grep usb for 
instance:

cat /proc/interrupts | grep usb
  16:      39179        307   IO-APIC-fasteoi   uhci_hcd:usb3, mmc0, 
firewire_ohci, jmb38x_ms:slot0, eth1, nvidia
  17:          0          0   IO-APIC-fasteoi   uhci_hcd:usb4
  18:          0          0   IO-APIC-fasteoi   ehci_hcd:usb1, uhci_hcd:usb7
  19:          0          0   IO-APIC-fasteoi   uhci_hcd:usb8
  20:          9          9   IO-APIC-fasteoi   ehci_hcd:usb2, uhci_hcd:usb5
  22:          0          0   IO-APIC-fasteoi   uhci_hcd:usb6

As you can see the bus ID's get prepended with ohci_hcd, ehci_hcd or 
uhci_hcd. So you have to write your bus ID's to the corresponding unbind 
file. In your case the one in /sys/bus/pci/drivers/ohci_hcd/.

Regards,

Jeremy