Hey folks...
I'd like someone out there to let me know if they can duplicate this condition on their motherboard, if it's a Z87 series motherboard.
SUMMARY: USB 3.0 header-connected ports not active at boot time if non-keyboard-device plugged into it, but both ports active if one is occupied by a keyboard.
Using my GA-Z87X-UD4H I've been having some troubles with which USB 3.0 ports are active at boot time. In particular, only the bottom/leftmost USB 3.0 ports on the motherboard were active at boot time. The top/rightmost two were not, and anything attached to either of the USB 3.0 headers was not.
After experimentation, I found the following:
With XHCI Mode set to "Smart Auto" (the default), the USB 3.0 ports behave differently depending upon what is plugged where - in particular:
With one of the USB 3.0 headers attached to 2 USB 3.0 ports on my case, I did the following:
1. Keyboard attached to one of the bottom USB 3.0 ports on the motherboard, USB 2.0 flash drive connected to one of the front USB 3.0 ports (from the USB 3.0 header) - RESULT: Keyboard worked, flash drive was not seen by BIOS
2. Keyboard attached to one of the front USB 3.0 ports (again, from the USB 3.0 header), AND same USB 2.0 flash drive connected to the other front port (from the same USB 3.0 header) - RESULT: Keyboard worked, flash drive WAS seen by the BIOS
... so it was as if attaching a keyboard to a port on one of the motherboard's USB 3.0 headers activated the 2 ports on that header; without the keyboard attached to it, the flash drive was not seen by the BIOS.
Why would this happen? This seems like strange behavior - is this some sort of expected behavior? Seems awfully odd to me.
- Tim
