Override boot console default refresh rate linux kernel

Its annoying if you switch from X Display to console (CTRL+ALT+F1) and you have to wait everytime until the monitor has switched from X (50Hz) to its default console 60Hz. If you want 50Hz on console from boot you can do it by:

How to set default refresh rate for HDMI monitors console right after kernel boot?
get a list of connected monitors:

for p in /sys/class/drm/*/status; do con=${p%/status}; echo -n "${con#*/card?-}: "; cat $p; done

add/append to kernel command line:

video=HDMI-A-1:1920x1080@50

If you have more than one monitor simply append the others:

video=HDMI-A-1:1920x1080@50 video=HDMI-A-2:1920x1080@50 ...

Build kernel/reboot and enjoy switching between X and console without delay.

set 50 Hz on an 60 hz only samsung lcd linux

Problem: Samsung LCD (SA300) has no mode for 1920×1080@50. 50Hz are needed for smooth playback of europe/pal based tv/video (25fps). Solution: I have another LCD that can do 1920×1080@50. Use xrandr and xvidtune. I set it to 50Hz with „xrandr -r 50“ . Now start xvidtune and press „Show“.  This prints the 50Hz modeline, in my case:

„1920×1080“ 148.50 1920 2448 2492 2640 1080 1084 1089 1125 -hsync +vsync

Now I can use this modeline to set my secondary (non 50Hz) monitor (VGA1) to 50Hz:

xrandr –newmode „1080@50Hz“ 148.50 1920 2448 2492 2640 1080 1084 1089 1125 -hsync +vsync

xrandr –addmode VGA1 1080@50Hz

xrandr –output VGA1 –right-of HDMI1 –mode 1080@50Hz

I dont know why it works but I guess because my monitors have quite the same properties (same native resolution). But it could maybe also destroy your monitor!