rEFInd and Psychology Software Tools button box

[Chuck Theobald]

We run fMRI experiments here and use the PST button boxes for participant responses. I find that if the button box is connected to my iMac, I get a dark screen. Unplugging the USB cable or starting with it unplugged causes rEFInd to show its icon screen, but this is inconvenient and adds wear and tear to the cable.

First, why would this HID cause rEFInd to not display the menu? Second, how can this be fixed?

Thank you,
Chuck

[Roderick W. Smith]

Button boxes! That brings back memories! In a past life I was an experimental psychologist, and ran experiments with such things. This was before USB was invented, mind you; they used RS-232 serial connections, IIRC.

In any event, this sounds like an EFI issue initializing the USB ports. Certainly there's nothing in rEFInd that looks for USB devices per se -- the closest is the disk-scanning code, which can pick up USB flash drives. Even that doesn't contain any explicit references to USB; it just scans for disk devices, and if they happen to be USB, it picks them up. Do you know if the computer boots OK with the button box plugged in and rEFInd not installed (or bypassed by using the startup disk tool in OS X)? If so, then there's some unintended interaction that we might be able to debug (I'd need to send you debugging versions of rEFInd for testing). If the computer fails to boot with the button box plugged in and rEFInd out of the loop, then there's not much I can do about it, I'm afraid.

As a workaround, you might consider looking for USB hubs that have switchable ports. Such devices should let you turn off an individual USB device by flipping a switch, which will at least save wear and tear on the computer's and button box's hardware.