USB KVM FAQ
SuperKVM USB KVM FAQ—no picture troubleshooting, driver-free notes, U-disk/SD, OTA, permissions, loop-out, and client compatibility.
USB KVM FAQ Answer first: Most “no picture” issues come from cable order, loose HDMI, or the host not enumerating the camera/serial device. New USB devices on host and target are typically driver free. Use the steps below with /en US/hardware/usb. 1. Unable to see remote desktop after connecting laptop to KVM device in browser? Troubleshooting steps: Recheck and reconnect cables, following the order of host first, then target. First connect the host USB cable, then connect the target USB cable and HDMI input. The HDMI cable must be inserted tightly, otherwise you won't see the remote desktop Observe the LED, and make a preliminary judgment based on LED Status Confirm whether the camera and UART hardware drivers on the host side are successful (LOOP, USB, and Pro versions have slight differences in VID PID and device names, you need to identify them yourself, especially if you have modified the VID PID): Apple system: Apple logo in the upper left corner About This Mac More Info System Report USB Windows: My Computer Management Device Manager Linux (Ubuntu): a. Confirm camera: sudo apt install guvcview, then click guvcview, confirm if there is a USB video related device in the device list b. Confirm serial port: ls la /dev/ttyACM0 , if the device exists, it means the USB to serial hardware driver device is normal c. Confirm USB camera: ls la /dev/video , usually video0 and video1 devices, we use video0 by default d. On Ubuntu like systems, the current user must be added to the video and dialout groups, sudo usermod a G dialout $USER , otherwise camera and serial devices cannot be accessed; after changing groups, log out and log back in for the change to take effect; if it still does not work, install firmware packages with: apt install linux firmware e. Other things to try: If the hardware is normal but still cannot display the desktop, troubleshoot the software: Close Chrome (preferably Chrome browser), reopen it Check if there are any abnormal Chrome processes in the background, if so, manually exit them If there is a permission prompt, please follow the prompt to enable camera and serial port access permissions 2. What devices does the host computer recognize after connecting USB devices to the host? USB hub, USB camera, CDC serial port, USB card reader (optional) 3. What devices does the target computer recognize after connecting the USB KVM device to the target? USB hub, keyboard, mouse, USB card reader (optional) 4. What drivers need to be installed on the computer when using USB KVM device? After connecting the KVM device, all newly added devices on both the host side and target side are driver free, so no driver installation is needed, just plug and use 5. How to use SD card? If you don't need to install the system or transfer files, you don't need to insert an SD card The KVM hardware implements an SD card reader. After inserting the SD card, it will be recognized as a USB drive with USB 2.0 speed. Both the target and host sides have 2.0 read speed. Even if the loop version has 3.0 USB interface and hub, because the card reader chip is 2.0, the 3.0 host reading SD speed is also USB 2.0 speed 6. How to install system on SD card? First, put the SD card into a USB card reader, use USB boot disk creation software like Ventoy to create a USB boot disk, then put the ISO file to be installed into the boot disk. The system will recognize it as a USB boot disk. Note: when installing the system, you need to correctly switch the USB drive direction 7. Can loop device be used on Switch? Yes 8. Can loop device work without connecting loop out display? Yes 9. Can the web client currently paste Chinese, images, and transfer files? No, currently only one way pasting English from host to target is supported. Bidirectional clipboard feature needs to be implemented first 10. Can the VID PID of the USB hub generated by KVM be modified? No 11. How to control the loop out resolution of loop version? Maximum support 4K@60Hz, specific depends
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