Comment # 7 on bug 91202 from Guido Winkelmann

Can confirm the problem with an R9 285 chip (graphics card is called ASUS
STRIX-R9285-DC2OC-2GD5).

The monitor receives no input (switching to power saving mode) when run at its
preferred resolution of 2560x1440. It will work with any other resolution, but
switching it back 2560x1440 will disable it again.

This is with Kernel 4.3 and the amdgpu driver from today's git master.