Hi everyone,
we are observing a strange issue with a CSI camera (YUV, passthrough) and the TX2 evalboard. As long as a monitor via HDMI is connected, the images from the camera are fine. But once the monitor is unplugged, no images can be acquired. We have checked the signals on the CSI lanes with a MIPI analyzer and even there the effect is visible.
Do you have any idea/hints for further investigation? Might it be that the Mipi lane termination resistors are somehow tied to the HDMI port?
may I know what’s your test pipeline, had you rendering the camera frames to the display?
it’s EGL stream for rendering display image. you may replace element by fakesink if display monitor disconnected.
here’s an example to disable preview and shows frame-rate only $ gst-launch-1.0 nvarguscamerasrc sensor-id=0 ! 'video/x-raw(memory:NVMM),width=1920, height=1080, framerate=30/1, format=NV12' ! nvvidconv ! 'video/x-raw(memory:NVMM),format=I420' ! fpsdisplaysink text-overlay=0 video-sink=fakesink sync=0 -v
thanks for your response. The camera provides YUV data. So libargus and gstreamer are not involved, the streaming happens directly via V4L. We don’t display the camera image on the screen.
Attached are two screenshots from the mipi analyzer. One with hdmi connected (all green) and one without hdmi (all red). As you can see, the issues are already visible on the electrical side. So I suspect that it’s an issue of the receiving software.
what exactly do you mean by v4l pipeline? As noted, gstreamer is not used here. The drivers for this camera live in userland, so it’s not a self-contained v4l device. The wrong data-type seen in the second analyzer screenshot is misleading. The whole mipi signal is disturbed (The checksum of every packet is wrong).
Is there any known issue regarding the CSI termination resistors, or anything else that might disturb the electrical signal?
please refer to developer guide for the sample commands.
it’s the application using V4L2 IOCTL directly, which uses V4L2 IOCTL to verify basic functionality during sensor bringup.
I don’t understand this, could you please describe more details about the environment setup.
