[General Questions and Answers] RMasterJ:
Hi all,

My goal is to to connect Fire TV and Chromecast devices to touchscreen displays, interacting with them similar to Android phones. I had hoped that touch input would be available out of the box but that is not the case. After much searching, it seems that touch input drivers are not included with either Fire OS or Google TV. Getting touch input working may require compiling the HID-Multitouch drivers and loading them into the kernels of Fire OS and Google TV.

I have some experience compiling from source on Linux, for Linux devices. I have no experience compiling from source for Android, Fire OS, or Google TV.

Questions:

Has anyone gotten touch to work on these devices?

Would a pre-compiled kernel module for Linux or Android work with Fire OS and Google TV kernels or do the drivers need to be compiled specifically for these devices?

If compiling specifically for these devices is required, what is the best approach be for someone who has never compiled anything for those devices before?

Desired state is a device that can connect to portable touchscreens via single USB connection and do not require additional devices (remotes) for user interaction.

The Zenscreen that I'm currently using supports HDMI input and touch output over USB-C but the monitor isn't capable of reverse charging. As a result, the USB-C hubs are needed in order to provide power to the Fire TV and Chromecast. If touch can be made to function practically the Zenscreen will be replaced with a portable touchscreen that supports reverse - possibly the 4K Uperfect.

Fire Stick is not capable of connecting via single USB port due to the limitations of the USB v2.0 Micro-USB port. It will require HDMI and USB cables to be connected to operate with touch.

Chromecast USB-C port capabilities are unclear and the USB version is not listed by Google. The device does not output HDMI over USB-C out of the box and I haven't determined whether that is due to software or hardware limitations.

Both devices output HDMI to the Zenscreen with the GQeeM HDMI to Micro-HDMI adapter and both devices accept power from the dockteck hub. The Fire TV also accepts power from the Apple hub.

The order of connection is USB-C charger --> USB-C hub --> (Chromecast or Fire Stick) --> HDMI to Micro-HDMI --> Zenscreen (via Micro-HDMI).

HID-Multitouch is connected to the hubs from the Zenscreen's USB-C port through a USB-A to USB-C cable.

Problems

Fire Stick and the Chromecast both fail to recognize the HID-Multitouch input device.

Chromecast complains about power from the Apple hub. Apple doesn't publish the power output specifications. According to this (unrelated) article the Apple hub should be capable of negotiating 7.5w (5v @ 1.5) output but there seems to be a problem with the negotiation and it's likely that the Chromecast is only receiving 5w (5v @ 1a).

Zenscreen was connected to laptop using the Micro-HDMI port and a USB-C cable in order to validate that the monitor outputs touch commands over USB-C while the Micro-HDMI input is active.

Devices & Versions

Fire TV Stick 4K: Fire OS 6.2.8.0 (NS6280/3233)

Chromecast w/ Google TV: Build Number: 210311.008 7350836

USB-C Hubs

Apple USB-C Digital AV Multiport Adapter

dockteck 4-in-1 USB C Hub with 4K@60Hz HDMI HDR, 100W PD

HID-Touch Panel

ASUS ZenScreen Touch MB16AMT USB Portable Monitor

HDMI to Micro-HDMI Adapter

QGeeM Micro HDMI to HDMI Adapter