Re: [gentoo-user] Powering down the USB controller

[Grant]

>> I'm trying to get a USB sound card to behave in a certain way which
>> requires it to think the computer has gone to sleep.  I'm told the
>> specific signal the sound card looks for is if the USB controller has
>> been physically powered down.  Should I unload a kernel module to
>> accomplish this, or do I need to actually put the computer into sleep
>> mode?
>
> I don't think you can turn USB port off, at best you can suspend it,
> which is not truly 100% powered-down. I think you might be able to
> power off an entire hub (and never power it back on again until
> reboot) but I'm not sure if that will be any better than just
> unplugging the cable. You might be able to build some kind of simple
> USB on/off switch. :)
>
> Check out /sys/bus/usb/devices/[yourdevice]/power/level for current
> status and you can echo different commands to that same file to
> attempt to change its status. Check out the power management settings
> and documentation in the linux kernel for your options.

Will do, thanks Paul.

- Grant