With KMS enabled on Xubuntu 11.04, my virtual terminals are running at 60hz, the default for my monitor, while my X desktop is running at 75, the refresh rate I specified in my xorg.conf. How do I set the refresh rate/mode used by KMS so that it is something different from the default mode provided by my monitor?
You can specify the resolution/refresh rate that the VT framebuffers will use on the kernel command line¹.
To do so, you want to add
to your kernel command line. So, for example
would give you a
1024x768 framebuffer at 75Hz. The
@<refresh> bit is optional.
You can edit your kernel command line on a one-time basis by hitting
e from the grub menu, or to set it permanently you can edit
/etc/default/grub, adding it to the line
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video=1024x768@75"
/etc/default/grub you'll need to run
sudo update-grub to propagate the configuration to your boot settings.
Documentation/fb/modedb.txt has the full specification of what options you can pass in to
video= - if you have unusual requirements (interlaced, reduced-blanking, etc) see this documentation.
¹: This is due in part to the fact that there's no good way to notify VT users of resolution changes.