joesan

I've read numerous different posts here and there regarding setting up a USB Hub to avoid USB wake issues on the Mini. However I can't seem to find the exact process detailed anywhere.

I am thinking it goes along the lines of - All USB cables are plugged into the Hub, the Hub is plugged into the Mac Mini. And I seem to recall that the idea is to remove the bus power to the Hub so that power is only supplied by the PSU on switch on.


Is this correct or am I missing something?

What is the best way to cut the Bus Power?

Jirka Jirout

Just isolate the + contact on the USB connector. Use an adhesive tape or a paper adhesive label.

Warning: some hubs *always* power the logic from the USB bus and only use the external power to feed the attached devices. This is usually accomplished by using a diode between the +5V contact of the USB connector and the +5V contact of the external power connector. If this is your case, you can just remove the diode and replace it with a wire connection. Then you can isolate the +5V on the USB connector as mentioned previously.

If you do this, also disconnect the ACPI. Then you can put the computer to sleep automatically after the USB hub disappears and have it awaken automatically when the hub power has been re-applied.

joesan

Thanks Jirka. I covered Pin 1 on the receptacle with some adhesive tape.

To verify that I didn't have the warning situation that you mentioned I went in to Systems Profiler to check. With the only the master USB wire and no power connected to the Hub it did not appear in the profiler. When I additionally added the +5V power the hub and it's connected devices did appear in the Systems profiler. I am surmising that this is correct situation.

As regards bypassing the ACPI/iSense - is there an applescript for wake on the USB Hub appearing or do we use some internal setting in the Mini?

Jirka Jirout

Yes, what you describe is the correct and desired behaviour and you can use your hub without a modification.

iSense is a different thing, that has nothing to do with our situation ;-) As for the wake-up script, none is needed - the mini wakes up automatically whenever it detects any activity on the USB. What you need is something to put the Mac to sleep.

In QCar, we have two different options: we either watch a presence of particular device (typically the GPS receiver) or better its "file" in the /dev/ folder. Alternatively you can get the number of hubs on the bus using ioreg, something like this:

ioreg | grep -c USBHub

and whenever the result is lower than the expected number of hubs on your system (i.e. one or more are powered down), you go to sleep.

joesan

Thanks Jirka. I am planning on using Qcar so I'll wait for that implementation before I base the Mini's sleep on USB activity.

inov8tr

I went thru a lot of the same issues. This is what I came up with.....

http://inov8tr.blogs.com/scooby/2006...b_solutio.html

I have a hub that powers the logic via the USB connection and the bus power powers the devices. I decided the power drain was so minimal for the logic that it was fine to leave on with the sleeping mac mini, as the usb ports are still powered during sleep. I have left my car unstarted for 3-4 days without issue.

My setup has been installed for 9 months now and there has been zero issue with the usb hub and devices connected to it. Let me know if you have any questions....

-INOV8Tr

joesan

Thanks for the info. I think I've got there using Jirka's setup.

Here's a twist - I've got a Carnetix P2140 that, thanks to the PSUmoni port by Ondra, can communicate with the Mac via USB.

Is it best to connect the powered hub to the Mac and then connect the P2140's USB cable to the hub or should I connect the P2140 USB cable direct to the Mac? Eventually I'd like to use the USB control of shutdown in Qcar.