Comment # 1 on bug 105534 from Alex Deucher

Please attach your dmesg output.  Note that Raven does not support dual-link
DVI.  There is only a single digital encoder connected to each connector on the
motherboards.  You need two encoders (one for each link) per connector to run
dual link DVI.  You need to use native DP or HDMI for high res modes.