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Driver for Enhanced Host Controller Interface (EHCI) USB controllers

Note: You must be root to start this driver.


io-usb -d ehci [option[,option...]] &

Runs on:

x86, MIPS, ARM, PPC, and SH


Interrupt microframe threshold. Valid values are 1,2,4,8,16,32,64. The default value is 8, which is a 1ms interrupt rate. The chip will interrupt after a 1ms period (USB frame) if there are completed transactions. Setting the value to 1 lets the chip interrupt after 125us (USB microframe) if there are completed transactions.
Register the base address. The default is to scan the PCI bus.
The interrupt request number.
Don't disable system management. The default is to disable it.
The number of endpoint descriptors to preallocate.
The number of transfer descriptors to preallocate.
Instance of controller on PCI bus to apply argument.
Set verbosity level.


The server provides support for computers that have Enhanced Host Controller Interface (EHCI) USB controllers. This server creates the /dev/io-usb/ device.


Scan PCI bus for all available controllers.

io-usb -dehci

If you specify arguments you'll need to include pindex arguments for all controllers you wish to use. The value for the pindex argument should start from 0. Attach to the 1st and 3rd controller instance and set the verbose argument on the 1st, as follows:

io-usb -dehci pindex=0,verbose=4,pindex=2 &

See also:,, io-usb, usb

Connecting Hardware in the Neutrino User's Guide