Pcsx2

Install

sudo pacman -S pcsx2

Install bios to ~/.config/PCSX2/bios. See /mnt/games/PS2/__bios__.

Configuration

Manual

You'll also need to adjust the plugins libgsnull renders as a black screen.

Config > Plugin/BIOS Selector:
    GS: GSdx
    PAD: OnePAD    # manual config
    SPU: SPU2-X

Settings Locations

~/.config/PCSX2	root settings dir
~/.config/PCSX2/PCSX2-reg.ini	determines where settings are saved-to/read from
~/.config/PCSX2/inis_1.4.0/PCSX2_ui.ini	Where to find isos, which plugins, which bios.
~/.config/PCSX2/inis_1.4.0/*.ini	See PCSX2-reg.ini to know the exact version. This is where your settings are actually stored.

# inis_1.4.0/PCSX2_ui.ini
[Folders]
RunIso=/mnt/games/PS2    # dir that opens by default

[Filenames]
GS=/usr/lib32/pcsx2/libGSdx-1.0.0.so
PAD=/usr/lib32/pcsx2/libonepad-1.1.0.so
SPU2=/usr/lib32/pcsx2/libspu2x-2.0.0.so
BIOS=/home/will/.config/PCSX2/bios/scph39001.bin