https://bugs.freedesktop.org/show_bug.cgi?id=52266
--- Comment #8 from Alex Deucher agd5f@yahoo.com 2012-07-20 13:53:02 PDT --- Created attachment 64449 --> https://bugs.freedesktop.org/attachment.cgi?id=64449 possible fix
How about this one? If it doesn't work, try commenting out the first *ddc_i2c line and uncommenting the second:
+ *ddc_i2c = combios_setup_i2c_bus(rdev, DDC_DVI, 0, 0); + //*ddc_i2c = combios_setup_i2c_bus(rdev, DDC_VGA, 0, 0);
Let me know if either of those work.