Mostafa Shahverdy composed on 2016-05-30 17:53 (UTC+0430):
I have an ultra wide monitor that supports 2560x1080. While I have a Radeon 5450 graphic card, running Debian Sid, I only can get 1920x1080. I installed firmware-linux-nonfree to get it running. So why isn't my complete resolution listed?
I can't answer why, at least, not without seeing your Xorg.0.log. Does it show the FBDEV or VESA driver being used rather than modeset or RADEON?
I don't have Sid on a 5450 system, but I do have Wheezy on a 5450, which does refuse 2560x1080. Same machine also has openSUSE 42.1, which was released last November, and does do 2560x1080 whether on VGA output or HDMI output, using the modeset driver built into Xorg 1.17.2 server itself.
There should be no need for the AMD/ATI/Radeon driver when using recent server versions with most gfxchips that are new enough, as the 5450 is.
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