DRIVE OS Version: Provide DRIVE OS version. Example: 7.0.3
Hi NVIDIA team,
I want to determine through software, whether the display is connected. Though the display is connected, xrandr shows “Can’t open display :0”. Additionally, cat /sys/class/drm/card1-DP-1/status returns “No such file or directory”.
Please suggest how to detect if a DP (DisplayPort) monitor has been plugged in?
From software perspective, If I follow steps as per Setting Up the Display with OpenWFD and EGL Device — NVIDIA DriveOS 7.0.3 Linux SDK Developer Guide
device creation fails at step 2 wfdCreateDevice().
Can I use openWFD APIs to check whether display is connected or disconnected, and whether the configuration is right? If not can you please suggest a better approach?
Please let me know if more details are required.
Thank you!
Dear @divya.bilimoria ,
Do you see any messages in dmesg or /var/log/syslog indicating dp port connection?
with the display physically connected attaching the output at /var/log/syslog–(output1.txt)
Also, cat /sys/class/drm/*/status returns disconnected for all ports eg: for card0-DP-1, card0-HDMI_A-1 status = disconnected
output1.txt (22.5 KB)
Do you see display coming? could you share complete syslog?
After flashing the target with DOS 7.0.3, with monitor connected to target, I can see entries like below in syslog. Could you try changing the monitor and see if similar entries can be noticed?
2026-06-09T02:42:29.399899+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): DELL U2415 (DFP-0): connected
2026-06-09T02:42:29.399944+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): DELL U2415 (DFP-0): Internal DisplayPort
2026-06-09T02:42:29.399977+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): DELL U2415 (DFP-0): DFP is not internal to notebook
2026-06-09T02:42:29.399991+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): DELL U2415 (DFP-0) Name Aliases
2026-06-09T02:42:29.400029+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): DFP
2026-06-09T02:42:29.400043+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): DFP-0
2026-06-09T02:42:29.400060+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): DPY-0
2026-06-09T02:42:29.400099+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): DP-0
2026-06-09T02:42:29.400143+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): DPY-EDID-5abfc6ba-5034-77e3-711d-db3010a62a6a
2026-06-09T02:42:29.400157+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): DP-0
2026-06-09T02:42:29.400175+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): Connector-0
2026-06-09T02:42:29.400203+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): DELL U2415 (DFP-0): 2380.0 MHz maximum pixel clock
2026-06-09T02:42:29.400243+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0):
2026-06-09T02:42:29.400287+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): --- EDID for DELL U2415 (DP-0) ---
2026-06-09T02:42:29.400301+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): EDID Version : 1.4
2026-06-09T02:42:29.400320+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): Manufacturer : DEL
2026-06-09T02:42:29.400334+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): Monitor Name : DELL U2415
2026-06-09T02:42:29.400371+00:00 tegra-ubuntu /usr/libexec/gdm-x-session[2482]: (--) NVIDIA(GPU-0): Product ID : 0xa0b9
hello @SivaRamaKrishnaNV ,
when the display is connected, the Thor login screen come up on physical display.
And syslog shows
And
Hello @SivaRamaKrishnaNV
kindly can you share your comments based on observations I have shared?
Does that mean you have seen login screen now? what is the issue?
Login screen shows up, I see syslog as below:
But still /sys/class/drm does not show DP/HDMI port:
So as stated initially question still remains, how to detect if a DP (DisplayPort) monitor has been plugged in?
Can I use openWFD APIs to check whether display is connected or disconnected, and whether the configuration is right? OR Is there alternative, can you please suggest a better approach?
We want to read out display status and configuration for Display related fault detection requirement implementation.
Hello @SivaRamaKrishnaNV
kindly can you provide comments based on observations I have shared?
Dear @divya.bilimoria ,
Could you share cat /sys/module/nvidia_drm/parameters/modeset ?
I notice below on my target
nvidia@tegra-ubuntu:~$ sudo cat /sys/module/nvidia_drm/parameters/modeset
Y
nvidia@tegra-ubuntu:~$ ls /sys/class/drm/
card0 card1 card1-DP-1 renderD128 renderD129 version
If you notice cat /sys/module/nvidia_drm/parameters/modeset as N, try reloading nvidia-drm with modeset set to 1
sudo rmmod nvidia-drm
sudo modprobe nvidia-drm modeset=1
cat /sys/module/nvidia_drm/parameters/modeset
ls /sys/class/drm/
Dear @divya.bilimoria ,
Could you please check above suggestion and update?
Hi @SivaRamaKrishnaNV ,
As per your suggestion I peformed manual modeset and with cat /sys/class/drm/card1-DP-1/status was able to see display status as connected.
Does this setting need to be incorporated in boot sequence, how?
Dear @divya.bilimoria ,
Noticed this issue on DOS 7.0.3 release and WAR is provided. In next release, it should should work out of the box. Can you check if systemd service works?
do you mean to check nvidia-drm service in systemd?
It shows unit service could not be found
Dear @divya.bilimoria ,
I meant to check if the steps can be included as systemd service or can be part of bashrc and make sure it runs if /sys/module/nvidia_drm/parameters/modeset is N .
