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 EHCIVendor 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/35991The 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...? 
Booting from install disk, no USB keyboard
arch linux;usb;system installation;bios
The kernel used on the August 2013 install disk, 3.10.4, apparently doesn't include support for the Logitech Unifying Receiver. The problem seems to have been fixed in the 3.10.6 kernel: after I installed Arch using a wired keyboard, my wireless keyboard worked fine using the unifying receiver with the Arch kernel that was installed (3.10.6). I also compiled my own 3.10.7 kernel and my wireless keyboard is still working.Most of the bug reports and forum posts relating to this issue come from Arch websites, but I found a post from a Ubuntu user, so this may or may not be a more general problem.