https://bugs.freedesktop.org/show_bug.cgi?id=109957
--- Comment #2 from Ricardo Ribalda ricardo.ribalda@gmail.com --- As a side note, amdgpu driver on a different card can use the screen properly with the same modeline:
00:01.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Carrizo [1002:9874] (rev 84)