This bug affects also me. I just upgraded from 14.04 and 16.04 (4.4.0-28-generic #47-Ubuntu SMP kernel) radeon driver offers only 1024 x 768 resolution. Hw is adm redwood xt (hd 5670) which can do 1920 x 1080 at least.
I can run series of tests for you if needed.
This bug affects also me. I just upgraded from 14.04 and 16.04 (4.4.0-28-generic #47-Ubuntu SMP kernel) radeon driver offers only 1024 x 768 resolution. Hw is adm redwood xt (hd 5670) which can do 1920 x 1080 at least.
I can run series of tests for you if needed.