raspberrypi-fast-ts

A faster, lower-latency, userspace touchscreen input driver for the official Raspberry Pi 7" screen.

Compatibility

Only tested on Pi 4. It's possible it works on Pi 3 too. Will not work on Pi 2 or 1.

Installation Instructions

$ git clone https://github.com/ardera/raspberrypi-fast-ts.git
$ cd raspberrypi-fast-ts
$ make
$ sudo make install

After that, the driver is installed, but not yet enabled. To enable it and disable the old driver, see the following steps. Be aware this makes changes to /boot/config.txt. The installation script is rather dumb. If your config.txt is heavily modified, you can apply the changes manually, just look at how the Makefile does it.

$ sudo make enable

If you specified lcd_rotate=2 inside /boot/config.txt to rotate your display by 180 degrees, you also need to invoke raspberrypi-fast-ts with the -f option.

1. Open /etc/systemd/system/raspberrypi-fast-ts.service using your favorite text editor
2. find the line where it says ExecStart=/usr/local/bin/raspberrypi-fast-ts
3. change it to ExecStart=/usr/local/bin/raspberrypi-fast-ts -f

After a reboot, the new driver will be used.

Switching back to the old driver

To switch back to the old driver:

• remove the 5 last lines of /boot/config.txt
• remove the uinput line from /etc/modules
• run sudo systemctl disable raspberrypi-fast-ts.service

Backlight interface

This driver now has a backlight interface similiar to the standard sysfs one. It's located inside /var/tmp/raspberrypi-fast-ts. Currently, bl_power and brightness are supported.

You can use it just like the sysfs interface, for example to change the brightness to 50%:

$ sudo bash
# echo 127 > /var/tmp/raspberrypi-fast-ts/brightness
# exit

to change it to 100% again:

$ sudo bash
# echo 255 > /var/tmp/raspberrypi-fast-ts/brightness
# exit