4K DISPLAY FRAMERATE SETTING

Hello,

With reference to my old case

Here I want to restart this discussion.
As in my old case I was using regular OS of Nvidia Jetson ubuntu 18.04.
I had my custom carrier board on which I am using Jetson Nano SOM.
Due to some design limitation I can’t able to support HDMI out 4K resolution at 60 FPS.
I restricted it to 4K resolution at 30 FPS.
In regular OS using unity-monitor.xml file I can restrict display to 4K@30Hz. Its working fine.
Now I am working on custom OS which has only command line utility(miniOS version) .
In this OS I tried same method of unity-monitor.xml file but its not working.
Then I searched on forum so I got few links on configuring xorg.conf file.
I tried those methods but it won’t work.
Please guide me on configuring xorg.conf file to restrict display to 4K@30Hz.
Thanks.

Hello,

Thanks a lot for sharing link. I checked that link and with reference to given link and some other links add following in xorg.conf file.

Section “Device”
Identifier “Tegra0”
Driver “nvidia”
#Allow X server to be started even if no display devices are connected.
Option “AllowEmptyInitialConfiguration” “true”
Option “UseEdid” “False”
Option “Monitor-HDMI” “HDMI-0”
EndSection

Section “Monitor”
Identifier “HDMI-0”

 #1920x1080 @ 30.00 Hz (GTF) hsync: 32.97 kHz; pclk: 80.18 MHz

Modeline “1920x1080_30.00” 80.18 1920 1984 2176 2432 1080 1081 1084 1099

#Option “PreferredMode” “1920x1080_30.00”
EndSection

Section “Screen”
Identifier “Default Screen”
Device “Tegra0”
Monitor “HDMI-0”
DefaultDepth 24
Subsection “Display”
Depth 24
#Virtual 1920 1080
Modes “1920x1080_30.00”
Option “PreferredMode” “1920x1080_30.00”
EndSubsection
EndSection

If I comment line Virtual 1920 1080 then there is no effect on display.
But if I add this line then display resolution restrict to 1920x1080 but it is still select 60 fps not 30 fps.

Please guide me on this issue.
Thanks a lot for support.

Your xorg log will guide you more than me. Xorg log will tell you why this mode setting fails.

Hello,

Thanks a lot for suggestion.

I was trying to set up bydefault display to 3840x2160@30Hz, for that I check xrandr --verbose command and I got following details.
xrandr.txt (8.3 KB)

From above details I picked up 3840x2160 resolution and 30Hz frequency data and decide modline and edit xorg.conf file as follows,
xorg_conf.txt (1.3 KB)

But when I restart the system still I got 3840x2160@60Hz only then I check the xorg log.
xorg_log_090924_3.txt (245.5 KB)

In that I found out following,
[ 5.390] (WW) NVIDIA(GPU-0): Validating Mode “3840x2160_30”:
[ 5.390] (WW) NVIDIA(GPU-0): Mode Source: X Configuration file ModeLine
[ 5.390] (WW) NVIDIA(GPU-0): 3840 x 2160 @ 30 Hz
[ 5.390] (WW) NVIDIA(GPU-0): Pixel Clock : 297.00 MHz
[ 5.390] (WW) NVIDIA(GPU-0): HRes, HSyncStart : 3840, 4016
[ 5.390] (WW) NVIDIA(GPU-0): HSyncEnd, HTotal : 4104, 4400
[ 5.390] (WW) NVIDIA(GPU-0): VRes, VSyncStart : 2160, 2168
[ 5.390] (WW) NVIDIA(GPU-0): VSyncEnd, VTotal : 2178, 2250
[ 5.390] (WW) NVIDIA(GPU-0): H/V Polarity : +/+
[ 5.390] (WW) NVIDIA(GPU-0): Mode is rejected: Only modes from the NVIDIA X driver’s
[ 5.390] (WW) NVIDIA(GPU-0): predefined list and modes from the EDID are allowed
[ 5.390] (WW) NVIDIA(GPU-0): Mode “3840x2160_30” is invalid.

also ,
[ 6.160] (II) NVIDIA(0): Setting mode “DFP-0:3840x2160_30”
[ 6.332] (==) NVIDIA(0): Disabling shared memory pixmaps
[ 6.332] (==) NVIDIA(0): Backing store enabled
[ 6.332] (==) NVIDIA(0): Silken mouse enabled
[ 6.362] (==) NVIDIA(0): DPMS enabled
[ 6.363] (WW) NVIDIA(0): Option “monitor-HDMI” is not used
[ 6.363] (WW) NVIDIA(0): Option “PrefferedMode” is not used

It means that it allowing modes from EDID only.
But I choose mode and modline parameter from xrandr --verbose which shows EDID mode list

Then why this mode is invalid?
Please guide me on this issue.
Thanks a lot for support.

Then there is no method for it.

Hello,

Thanks a lot for reply.

Is there any other way where I can use xrandr command to set the resolution of display at the time of boot?

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