It is possible to use 2560x1080 resolution on Linux using ATI Radeon?

[cscs]

Maybe take a look through this thread…

Lots of display problems after installation of Manjaro KDE (Lysia)

Theres about a dozen ways to set resolution. With KDE I guess we could use kscreen-doctor … heres a quick one-liner I cooked up for you: mimon=$(xrandr | grep " connected" | cut -d' ' -f1); echo "Active screen recognized as "$mimon""; echo ""; echo "Desired resolution? (example: 1920x1080)"; read mires; kscreen-doctor output."$mimon".mode."$mires"@60

The answer there was basically some sort of bad configuration/driver … after a reinstall and such it worked.

Note - Towards the end is a script, but it was made for KDE (using kscreen-doctor).