For example, My screen is 4k, I want to set the HDMI to be 1080P. And How to get the current time sequence of HDMI（width height fps）
You can get the the modes by running:
sudo cat /sys/class/graphics/fb0/modes
And change the mode by executing
sudo echo 4 > /sys/class/graphics/fb0/blank sudo echo "U:3840x2160p-60" > /sys/class/graphics/fb0/mode sudo echo 0 > /sys/class/graphcis/fb0/blank
HA! I see.
What does the “U” means in “U:3840x2160p-60”? I can see “D” “V” “S” too.
And is there any API to do it?
I follow your command I can get the modes but can noe set the mode
It should work by simply put the string in
We have these TV modes:
nvidia@tegra-ubuntu:~$ sudo cat /sys/class/graphics/fb0/modes D:1920x1080p-60 D:1280x720p-60 V:640x480p-60 V:800x600p-60 V:1024x768p-60 S:1280x1024p-60 S:1600x900p-60 S:1152x864p-75 S:1680x1050p-60 U:3840x2160p-24 U:3840x2160p-25 U:3840x2160p-30 U:4096x2160p-24 U:1920x1080p-50
1.That means there is no api to set the mode?
2.What does the “U” means in “U:3840x2160p-60”? I can see “D” “V” “S” too.
We don’t have specific api for switching the mode. In Ubunut desktop, there is option in
System Settings →
Display and can switch the mode. It should be certain X functions for this. It would need other users to share experience.
The mode flag is checked in
fbsysfs.c - drivers/video/fbdev/core/fbsysfs.c - Linux source code (v4.10-rc8) - Bootlin
"U" means unknown.
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