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Keyboard + Mouse do not work

By Matthew McPeake @msmcpeake2021-04-05 22:42:08.402Z

Hi, trying to use this in a non standard setup I would assume. I have my Raspberry Pi connected to a KVM switch I have. The video is being shown, but no keystrokes go through. I can take a picture of the connector if you want, but my assumption was this just sent keyboard/mouse signals over the USB A cables?

Here are my logs with the errors I have been receiving. Let me know what information you need. Thanks!

https://logs.tinypilotkvm.com/zucEhxjV

  • 3 replies
  1. Michael Lynch @michael2021-04-06 18:38:33.980Z

    Thanks for reporting this. What's the model of your KVM?

    KVM compatibility is spotty because the Pi only has one port capable of emulating USB devices. Instead of presenting itself to the target computer as a USB keyboard or a USB mouse, it presents itself as a USB hub with a USB keyboard and USB mouse attached. Most KVMs expect direct connections to the USB keyboard and mouse, so they won't accept a connection through a USB hub.

    This page lists compatibility with various models of KVMs based on user reports:

    https://github.com/mtlynch/tinypilot/wiki/KVM-compatibility

    over the USB A cables?

    Just want to verify, you mean USB-C to USB-A, right? The cable has to be connected to the Pi's USB-C port for it to emulate a keyboard and mouse.

    1. M
      In reply tomsmcpeake:
      Matthew McPeake @msmcpeake2021-04-06 22:49:35.443Z

      Hi Michael, thanks for the reply.

      I am using the IOGEAR GCS1808KIT.

      https://www.amazon.com/gp/product/B002MAPS9O/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

      I saw somewhere else I needed an OTG hub for the USB cables, so that's how I have two USB A cables going to each keyboard and mouse USB port on the console dongle from the hub.

      Hub is a AUKEY brand hub that says it supports OTG capability.
      https://www.amazon.com/gp/product/B08DXPXPLK/ref=ppx_yo_dt_b_asin_title_o06_s01?ie=UTF8&psc=1

      I have moderate experience with Linux, is there any way I can map the keyboard and mouse to separate USB ports? I'd really love this to work as it looked like an awesome solution. I used to have a KVM console, but had to sell it, so I wanted to network my KVM switch.

      1. Michael Lynch @michael2021-04-07 19:14:27.205Z

        Hub is a AUKEY brand hub that says it supports OTG capability.
        https://www.amazon.com/gp/product/B08DXPXPLK/ref=ppx_yo_dt_b_asin_title_o06_s01?ie=UTF8&psc=1

        One thing you should watch out for there is reverse current. I don't think the USB OTG hub expects to be connected to two different power sources (the Pi and the KVM both have their own power), so it likely doesn't mitigate reverse current. See this wiki page for more details:

        https://github.com/mtlynch/tinypilot/wiki/Powering-your-TinyPilot-safely

        I have moderate experience with Linux, is there any way I can map the keyboard and mouse to separate USB ports? I'd really love this to work as it looked like an awesome solution. I used to have a KVM console, but had to sell it, so I wanted to network my KVM switch.

        I don't think that's possible. The Pi only has one USB OTG port, so you'd need a separate Linux device with a USB input and two USB outputs.

        If you can live with keyboard-only or mouse-only, you could flatten the TinyPilot to just a single USB keyboard or USB mouse device. The relevant code is here, installed on the device at /opt/tinypilot-privileged.