I booted stable Vivid, then dist-upgraded to Wily. When I open the Displays setting, the highest resolution I'm offered is 16:9 at 2560x1440. There's no option to go to 3440x1440, which is the native resolution of this monitor.
Debian unstable seems to have no problems displaying at the native resolution.
A few more data points.
I booted stable Vivid, then dist-upgraded to Wily. When I open the Displays setting, the highest resolution I'm offered is 16:9 at 2560x1440. There's no option to go to 3440x1440, which is the native resolution of this monitor.
Debian unstable seems to have no problems displaying at the native resolution.