Last month when testing the AMD Radeon HD 6550D
graphics as found on the AMD Fusion A8-3850
APU I mentioned the latest Git code (Linux kernel / Mesa / DDX) was broken for this Llano-generation APU while the proprietary Catalyst driver had "just worked" under Linux. Here's an update where the open-source driver support is now at today.
Now being back to the office, on Friday I pulled and built the latest Git components of the Radeon Linux graphics stack. When doing so, unfortunately, nothing had changed. The A8-3850 on the Gigabyte A75M-UD2H motherboard configuration still failed to properly light up the display when starting X, with the same problems as talked about (and shown) in last month's Llano graphics article. It didn't matter whether the display was using DVI, HDMI, or DisplayPort, but the same problem persisted.
AMD's Alex Deucher then mentioned to me, "I got a production Llano board this week and will be testing it out and fixing any remaining bugs. DVI and HDMI seem to work well on this board, but VGA is still having issues." It seems his production board is in better shape and that these current display problems may be motherboard-specific.
I've supplied Alex with a copy of the video BIOS for the Gigabyte A75M-UD2H so hopefully that will be fixed up soon. For now, it's just bound to using the AMD Catalyst driver on this motherboard, or the VESA driver if you really hate AMD's binary blob that much.