I'm trying to install Arch Linux on a new system with a Gigabyte GA-Z87N-WIFI board. Although I can use the USB keyboard (and mouse) in the BIOS, the keyboard doesn't seem to work at all once I boot off the boot DVD.
There are several people who've solved this problem by enabling IOMMU in the BIOS. I couldn't find an option called IOMMU, but I found VT-d, which I believe is the same thing. It's enabled.
Also, Arch detects my (wifi) network card and attempts to run DHCP on it. I don't know if this is relevant, but I think I remember reading that if IOMMU is disabled network cards aren't detected.
EDIT: I tried disabling UEFI in the BIOS, just in case... No change. I still have no keyboard.
EDIT 2: I think maybe appropriate kernel modules for my USB controllers aren't available (or aren't loading?) I went into hardware info from the install disk boot menu, and under PCI Devices, I can see three USB controllers. The "product" line reads:
8 Series/C220 Series Chipset Family EHCI
Vendor is Intel Corporation. Module is unknown. Maybe this is the issue? Most other devices have modules listed.
EDIT 3: This seems to be an issue with the install disk kernel, apparently it doesn't support the Logitech unifying receiver: https://bugs.archlinux.org/task/35991
The kernel mentioned in that bug report is in fact on the current 01/08/2013 install disk, and I have a unifying receiver. I managed to boot a Gentoo minimal install disk off a USB stick and the keyboard was fine. So I think I've answered my own question. Unless anyone has anything to add...?