I'm using Debian Buster, XFCE 4.12 as my DE, with an AMD RX 580 graphics card.
I have my primary monitor plugged on an HDMI port, and I wanted to use a secondary monitor on the DVI port, but this one is not detected.
At startup, the boot text is mirrored on both monitors, but at the lightdm greeter, only my primary monitor is on.
When I go to Settings > Display, only my primary monitor is detected
Only that display is detected by xrandr as well.
lshw -c video
*-display UNCLAIMED description: VGA compatible controller product: Polaris 20 XL [Radeon RX 580 2048SP] vendor: Advanced Micro Devices, Inc. [AMD/ATI] physical id: 0 bus info: pci@0000:06:00.0 version: ef width: 64 bits clock: 33MHz capabilities: pm pciexpress msi vga_controller bus_master cap_list configuration: latency=0 resources: memory:e0000000-efffffff memory:f0000000-f01fffff ioport:e000(size=256) memory:fe900000-fe93ffff memory:c0000-dffff
And for xrandr
xrandr: Failed to get size of gamma for output default Screen 0: minimum 640 x 480, current 1920 x 1080, maximum 1920 x 1080 default connected 1920x1080+0+0 0mm x 0mm 1920x1080 0.00* 1440x900 0.00 640x480 0.00
And info about the OS and the kernel
Linux debian-prout 4.19.0-5-amd64 #1 SMP Debian 4.19.37-5 (2019-06-19) x86_64 GNU/Linux
I suspect it is a problem with my drivers, but I can't figure out how to install/update them properly yet. I can see some text related to amdgpu firmware when I boot, but it's too fast I can't catch it.
What should I fix?