So the Radeon will be scanning out of the buffer that the Intel GPU has rendered to, but without waiting for that rendering to be complete. My guess as to the source of your problems is that, as of 16.04, there's no mechanism for synchronisation between the Radeon and Intel GPUs. The way these hybrid laptops tend to be set up is that the GPU driving the internal panel is switchable in the BIOS, but external displays are only connected to the discrete card. It's hard to say without looking at the X log, but I'd guess that things go pear shaped when you plug in a second monitor because the Intel GPU is doing all the rendering and driving the laptop panel but the Radeon is driving the external display¹. This means that when you've got “MSHYBRID” enabled in the BIOS the Radeon card is not connected to the panel - and, likewise, when you've got “DISCRETE” selected in the BIOS the iGPU is not connected to the panel. The longer answer is: unless you're on a Mac, it's likely that the BIOS switch actually reconfigures the internal display routing.

*Edit:* I just looked it up, the internal iGPU is an Intel(R) HD Graphics 4600 and the discrete is a AMD FirePro M5100 FireGL V (radeon driver is currently what I'm using for this) Is there any way without me having to go into BIOS all the time to switch X from iGPU to the radeon driver? I would be fine if I would have to restart X every time I wanted to switch but in all my googling I couldn't find a way to even get X to use my AMD GPU without going into BIOS and disabling switchable graphics. The only problem with this is that of course anytime I want to be portable I would want to use the iGPU to save battery (and for all portable purposes the iGPU does great). I guess the iGPU driver can't handle both external monitors through the Display port (that seems to be how the dock functions according to X stats). I finally got fed up enough to go into BIOS and disable switchable graphics just to test and now everything works awesomely.

I started getting some random graphical artifacts (though nothing major that I can't live with), the non-gaming normal FPS of those external monitors was atrocious (just moving the mouse around you could notice it). For the most part this was a great setup until I brought in a 2nd external (21:9 ultrawide) monitor and hooked it up to my docking station. It has both an Intel iGPU and an AMD Firepro card that I can't exactly remember at the moment (but only works with the standard radeon drivers).Įverything seems to be setup nicely at the moment where X uses the iGPU while I can DRI_PRIME=1 an application to force it to use my Firepro (for gaming and such). My laptop is a Dell Precision M4800, and so far running Ubuntu 16.05 on it has been a great experience with only tiny annoyances here and there.

Amd m5100 driver