I've just installed 828M, but I see it was happening earlier on 820M at least. After a fresh boot or restart, the front panel USB3.0 connector work correctly under control of XHCI at 5Gb/s. After waking from sleep, there is an error in system.log :
kernel: USBF: 2619.241 AppleUSBXHCI::RestoreControllerStateFromSleep - Error restoring controller state USBSTS = 0x401
and the USB3.0 is now controlled by EHCI instead of XHCI and down to 480Mb/s.
I tried toggling the XHCI handover in the BIOS, bu the machine locked up when I plugged in the external drive.
My case has no USB 3.0 front panel, I will get the cable separate and investigate...
AFAIK I have to repeat myself, but providing dumps will help in/to solve some of the issues, as you can see at this moment I can't reproduce your bug, you didn't mentioned the OS version, the bug may be caused by your specific usb adapter and so on...
just installed 828M bios. now sleep works and HDMI Sound. only no volume control from toolbar
thats no big deal for me .
Digital audio, that includes HDMI audio, has no control from toolbar, blame Apple for that, but is not a hack thing....