2

I want to use a dual screen for training in my school, so I have my Pi3 hooked up with HDMI to VGA adapter on display monitor and then usb to HDMI adapter to my LG smart TV.

on the smart TV, it shows device is connected but with message "No signal on the connected device.

Is this practice correct? I use the same USB to HDMI adapter on Windows for dual screen and no issue.

  • There are a few issues around using DisplayPort adapters (your USB adapter is using DisplayPort) with a Pi. I'm going to try and write up a sensible answer (or feel free to do it yourself!), but in the meantime you can take a look at this video for some pointers. – goobering Jan 27 '17 at 0:51
3

There's a tutorial (with a video demo'ing the system performance) posted at novaspirit.com with some instructions on reconfiguring the kernel to support USB DisplayLink devices. It's a little long to post in full. The gist of it is:

  • Git clone sources from https://github.com/raspberrypi/linux
  • Add missing dependencies (git libncurse5-dev bc)
  • Set the build configuration appropriately for your Pi model
  • Modify the default kernel configuration by enabling the Direct Rendering Manager (make menuconfig, then Device Drivers -> Graphic Support -> Direct Rendering Manager -> Enable)
  • Build and install the kernel, modules and Device Tree blobs
  • Edit /etc/X11/xorg.conf to reflect the new display configuration
  • Reboot

I've run a USB DisplayLink monitor connected to a Pi in the past and the performance was miserable, but the video attached to the linked tutorial actually looks pretty decent. A little laggy, and probably not best suited to running HD video, but usable.

  • Apparently in new os version etc/X11/xorg.conf is missing, do you have any clue what to do? I have recompiled the kernel but cannot get 2 screens up and running (probably I am missing this configuration which used to be in xorg.conf file) – Dawid Adach Nov 29 '18 at 14:27
0

The Pi does not support and cannot transmit video data to USB by default. You will need to recompile the kernel.

If you did, it would cause a very significant CPU/memory load.

Most people's multiple monitor setup utilize one Pi per monitor.

Related: Can I use usb port for display purposes?

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