Hello, we are currently using a custom Xavier NX motherboard paired with an Xavier NX 8GB core board. We want to achieve dual-screen output, but we cannot power on and use the device simultaneously by connecting both DP and HDMI. Connecting either HDMI or DP separately works fine. After powering on, connecting another monitor allows both screens to display simultaneously. The attached image shows the display that fails to power on when both screens are connected.
display.txt (17.8 KB)
If you have neither monitor plugged in, and monitor “dmesg --follow”, and plug them in one monitor at a time, what new log lines occur at each plug-in?
I saw hints that there might be a power issue. HDMI and DisplayPort provide configuration information over the DDC wire (it is an i2c protocol). Upon hot plug detect (which is why we are interested in what log is visible plugging in monitors one at a time) the i2c data is triggered. In order that monitors be detectable even when powered off the i2c circuitry is powered by the HDMI or DisplayPort cable, and sourced by the Jetson.
It is possible that if your device tree does not properly provide DC power for the i2c upon detect (or if no detect), then the i2c configuration will fail; the i2c power and the hot plug detect would need to function independently on both video cables, and this is a device tree function.