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GUD USB Display

A while back I had the idea to turn a Raspberry Pi Zero into a $5
USB to HDMI/SDTV/DPI display adapter.

GUD is an open USB display protocol.

A video to show how it performs with a Raspberry Pi Gadget: https://youtu.be/AhGZWwUm8JU

Images

There are USB gadget images for the Raspberry Pi

USB VID:PID

Ways to get a VID:PID

1. Become a member of the USB-IF and get a VID. The annual membership fee is US$5,000.

2. Buy a VID from USB-IF, the fee for this purchase is US$6,000.

3. Some companies are known to provide their microcontroller customers with a PID from their VID

4. Buy a USB Product ID for EUR 14.95+VAT

New VID:PID in old kernel

A UDEV rule can be used to add a VID:PID to a GUD kernel driver that doesn’t support it.

Show ID’s supported by the driver:

$ modinfo gud | grep alias
alias:          usb:v1D50p614Dd*dc*dsc*dp*icFFisc*ip*in*

Here is how to add support for 16d0:10a9 in a Linux v5.13 kernel:

/etc/udev/rules.d/40-usb-gud.rules

ACTION=="add", SUBSYSTEM=="usb", \
        ATTR{idVendor}=="16d0", ATTR{idProduct}=="10a9", \
        RUN+="/sbin/modprobe -b gud"

ACTION=="add", SUBSYSTEM=="drivers", ENV{DEVPATH}=="/bus/usb/drivers/gud", \
        ATTR{new_id}="16d0 10a9"