The last time I had to configure the Waveshare 3.5” LCD on my Raspberry Pi 3B (see How to Install Waveshare 3.5” LCD on Ubuntu 20.04) I ran into a lot of issues. I even automated the install/setup so I could replicate it if needed, saving me from having to deal with the over-complicated process.
Last week I had to re-image my Raspberry Pi 3B, that I use as my UPS controller, due to a faulty SD card. And to my surprise, the install and configuration of the LCD screen was another fiasco. The instructions on the Waveshare Wiki don’t work, and made me very frustated.
So to save you some time, and hair (it’s too late for me as I’m already bald), I have outlined the steps that worked for me.
Configure the Driver and OS
a. Update the OS
sudo apt update
b. Download the driver and copy it to /boot/overlays/
wget https://files.waveshare.com/wiki/common/Waveshare35a.zip
unzip ./Waveshare35a.zip
sudo cp waveshare35a.dtbo /boot/overlays/
c. Install the needed packages
sudo apt install --no-install-recommends xserver-xorg xinit lightdm -y
sudo apt install raspberrypi-ui-mods xserver-xorg-video-fbturbo -y
d. Configure /boot/firmware/config.txt
Comment out:
# Enable DRM VC4 V3D driver
#dtoverlay=vc4-kms-v3d <---
#max_framebuffers=2 <---
Add:
[all] # <--- Already exists
dtparam=spi=on
dtoverlay=waveshare35a
display_rotate=0
e. Disable 99-fbturbo.~ and 20-noglamor.conf
cd /usr/share/X11/xorg.conf.d/
sudo mv 99-fbturbo.~ 99-fbturbo.bak
sudo mv 20-noglamor.conf 20-noglamor.conf.bak
f. Create /usr/share/X11/xorg.conf.d/99-fbturbo.conf
Section "Device"
Identifier "Waveshare SPI LCD"
Driver "fbdev"
Option "fbdev" "/dev/fb1"
Option "SwapbuffersWait" "true"
EndSection
g. Fix Console/Splash Screen Mapping /boot/firmware/cmdline.txt
Append to end of the line:
fbcon=map:1
h. Disable lightdm
sudo systemctl disable lightdm.service
i. Set Console Autologin
sudo raspi-config nonint do_boot_behaviour B2
Configure Auto-Login for the Default User
This is the default user (with GID 1000), and it’s usually the ‘pi’ user. You can check the output of id, and the user set in /etc/systemd/system/getty@tty1.service.d/autologin.conf.
Here you can see that ‘johndoe’ is configured:
cat /etc/systemd/system/getty@tty1.service.d/autologin.conf
[Service]
ExecStart=
ExecStart=-/sbin/agetty --autologin johndoe --noclear %I $TERM
a. Add to ~/.bash_profile
startx 2> /tmp/xorg_errors
b. Add the video and tty groups
sudo usermod -aG tty,video [USER]
Reboot
reboot
Calibrate the Display
We will now calibrate the display to make sure that touches work properly.
a. Install the needed packages:
sudo apt install xserver-xorg-input-evdev xinput-calibrator -y
b. On the raspberry pi, run xinput_calibrator and touch the red dots. You can output to a file if you prefer to configure on another terminal after (e.g.: ssh)
xinput_calibrator > output_file
c. Copy the output to /etc/X11/xorg.conf.d/99-calibration.conf
$ xinput_calibrator
Calibrating standard Xorg driver "ADS7846 Touchscreen"
current calibration values: min_x=0, max_x=65535 and min_y=0, max_y=65535
If these values are estimated wrong, either supply it manually with the --precalib option, or run the 'get_precalib.sh' script to automatically get it (through HAL).
--> Making the calibration permanent <--
copy the snippet below into '/etc/X11/xorg.conf.d/99-calibration.conf' (/usr/share/X11/xorg.conf.d/ in some distro's)
Section "InputClass"
Identifier "calibration"
MatchDriver "evdev"
Option "MinX" "21663"
Option "MaxX" "22027"
Option "MinY" "48912"
Option "MaxY" "49185"
Option "SwapXY" "1" # unless it was already set to 1
Option "InvertX" "0" # unless it was already set
Option "InvertY" "0" # unless it was already set
EndSection
/etc/X11/xorg.conf.d/99-calibration.conf
Section "InputClass"
Identifier "calibration"
MatchDriver "evdev"
Option "MinX" "21663"
Option "MaxX" "22027"
Option "MinY" "48912"
Option "MaxY" "49185"
Option "SwapXY" "1" # unless it was already set to 1
Option "InvertX" "0" # unless it was already set
Option "InvertY" "0" # unless it was already set
EndSection
Note: Don’t copy my values. You should use the ones from your output.
d. Reboot
Conclusion
That’s it! You should now have a working X11 desktop on your 3.5” LCD. If you ran into any specific issues with Debian Trixie that I missed, or if you have different calibration values, feel free to drop a comment below.
