I recently built a computer and put a fresh install of Debian 9 on it. However when I plug both monitors into the Radeon RX 550 graphics card, my desktop is mirrored instead of extended. On top of this I have been unable to change the default size of 1024x768 to the actual monitor resolution of 1600x900. Running xrandr I get
xrandr: Failed to get size of gamma for output default Screen0: minimum 1024 x 768, curent 1024 x 768, maximum 1024 x 768 default connected primary 1024x768+0+0 0mm x 0mm 1024x768 76.00*
One monitor is plugged into the DVI port and the other is plugged into the HDMI port.
This problem persists on both i3wm and XFCE, though currently I'm using i3wm
The package "firmware-amd-graphics" is installed.
My X logs https://gist.github.com/anonymous/fc1bb91a4778c5a43efca4a854efb164
More recent X logs https://gist.github.com/anonymous/cb6a1f2f2f7d901245d5b8869cbad25c My xorg.conf https://gist.github.com/anonymous/6864f488ae8837966cfa3fffde059385