Thank you very much for sharing this!!!
It took me ages to find a solution, and now after doing this it works.
Further: (I use fedora 24)
In the startup of your computer there are 3 times that the resolution and refresh rate can be configured:
- grub
- xorg startup screen
- xorg user screen
Because the standard resolution doesnt work well with my monitor (why i still dont know) I wanted to change the resolution from 2560x1440 (144Hz) to 2560x1440 (120 Hz). I can tell you: that's a pain. (for me :-))
1. grub
First in grub you can change the resolution and refresh rate with grubby. In /etc/default/grub I have added: GRUB_CMDLINE_LINUX_DEFAULT="video=2560x1440@60" GRUB_GFXMODE="1920x1080,1280x1024" (the first line, (almost not documented), saved my life) after changing it, I typed: grub2-mkconfig
-o /boot/efi/EFI/fedora/grub.cfg (and not /boot/grub.cfg because I use EFI) Restart and the first config was changed succesfully with a refresh rate of 60HZ (120Hz didnt work)
2. xorg startup screen
cp /root/.config/monitors.xml /var/lib/gdm/.config/
3. xorg user screen
this resolution I've changed with the display manager in Xwindows
Further I have tried it with xorg.conf and /etc/X11/xorg.conf.d/XX-monitor.conf but unfortunately in Fedora 24 I can't get it work. It looks like xrandr or another proces is overruling those parameters.
