I have a laptop with the AMD Dual Graphics technology.
This technology contains AMD APU (Accelerated procesor) + AMD GPU (dedicated GPU) to work together in crossfire.
I know that this technology is designed for Windows in DirectX 10 and DirectX 11. But there are also a lot of issues with this combination.
I don't know, how to describe some issues, so I attached a screenshots.
CPU/APU: AMD A6-3400M with AMD Radeon HD 6520G APU
GPU: AMD Radeon HD 6470M
OS: Linux Mint 13 'Maya' 64bit
Drivers: AMD Catalyst Linux proprietary driver 13.1
Configuration: "amdconfig --initial" and "amdconfig --initial --adapter=all" - it's same
Crossfire don't work. But Catalyst let me at least to switch between both graphics cards.
This issues I didn't had on my previous laptop with only one AMD GPU, so, I'm assume that are caused by AMD Dual Graphics.
I tried: Cinnamon, Cinnamon 2D, MATE, Gnome 3, Xfce, Unity (on Ubuntu) - no difference
When I'm on 6520G APU:
1/ Taking a screenshots on Cinnamon
- For example: If I have Firefox minimalized in the taskbar and I do a screenshot of my desktop, I see Firefox on the screenshoot
2/ AMD Catalyst don't show the dedicated GPU
- I don't know, if this is a bug. I can post a screenshot, because I can't take screenshot on this graphics card - look at my "issue 1"
3/ vSync don't work
- There is a invisible line on the top of a screen where the vSync don't work. Look at screenshot 6520g_vsync.png.
- of course, I have "wait for vertical sync" - "always on"
When I'm on 6470M dedicated GPU:
1/ vSync don't work
- There is a invisible line on the top of a screen where the vSync don't work. Look at screenshot "6470m_vsync.png"
- The top part is rendered slower than the bottom one.
- Much worse than same issue on APU.
- I have "wait for vertical sync" on "always on"
- I can't capture it on screenshot, only on a photo, look at "vsync.jpg".
- It's much worse in movies and games
2/ AMD Catalyst shows both graphics cards
- I don't know, if this is a bug. On APU, I don't see this GPU (look at my "issue 2" on APU) and screenshot "both_gpus_on_6470m.png"
3/ AMD Vari-Bright don't work
- Vari-bright is always set to "maximize battery life". If I change it to any other value and confirm it by "apply", it will return back to "maximize battery life"
4/ Can't start TF2
- This is not happen on 6520G APU
- TF2 hangs on "loading ..." screen after Valve logo
- I waited more than 30 minutes, it never starts
5/ Display settings shows APU, no GPU
- I have activated the dedicated GPU 6470M, but in AMD catalyst, it shows AMD 6520G APU, look at screenshot "displays.png"