Waveshare 7.9" DSI screen setup help

Help and Support
1

Hi
I have been trying to setup a Waveshare 7.9" DSI screen on a raspberry Pi 4b. I have the most recent release of volumio installed.
I’ve managed to get the screen working but this breaks the WIFI! This is when I add the following to config.txt which i copied from the waveshare site -

dtoverlay=vc4-kms-v3d
#DSI1 Use
dtoverlay=vc4-kms-dsi-waveshare-panel,7_9_inch
#DSI0 Use
#dtoverlay=vc4-kms-dsi-waveshare-panel,7_9_inch,dsi0

I have tried various other suggestions from other posts on this forum, and they all end with the screen not working at all, but WIFI connected.

This is what i currently have in config.txt. Result is no output to screen.

DO NOT EDIT THIS FILE

APPLY CUSTOM PARAMETERS TO userconfig.txt

initramfs volumio.initrd
gpu_mem=128
gpu_mem_256=32
gpu_mem_512=32
gpu_mem_1024=128
max_usb_current=1
[pi5]
usb_max_current_enable=1
[all]
include volumioconfig.txt
include userconfig.txt

Volumio i2s setting below: do not alter

dtoverlay=hifiberry-dacplus

dtoverlay=vc4-kms-dsi-waveshare-panel-fixed,7_9_inch

2

what you got from the manufacturer’s site goes into /boot/userconfig.txt…NOT config.txt

3

Thank you for the reply.
I have made the change that you suggested and added this code to userconfig.txt -

 dtoverlay=vc4-kms-v3d
 #DSI1 Use
 dtoverlay=vc4-kms-dsi-waveshare-panel,7_9_inch
 #DSI0 Use
 #dtoverlay=vc4-kms-dsi-waveshare-panel,7_9_inch,dsi0

I am now back to the screen working working, but no network connection. Also the screen mapping is not correct i.e where I touch the screen the input is about an inch away.
I then removed this line from config.txt with the same end result -

dtoverlay=vc4-kms-dsi-waveshare-panel-fixed,7_9_inch

I appreciate the advice. Let me know ifI can provide any more info that may help resolve the problem.

*** Update***
I now have the network connected!
Just the screen mapping is not right. Any ideas?

4

Hi
I am still having problems with this setup. The screen is showing ok. But the problems are -

  1. No network. This worked on one of the start ups for a short time. On the network screen, I can see the WiFi, but it will not connect no matter how many times I enter the WiFi password. I have just disconnected the screen from the Pi and it connects to the network ok.
  2. The screen mapping is wrong, if I touch the center of the screen the cursor appears top right of the screen.

I’m at a loss for what to do!

5

Ok… For anyone reading this?
The power supply is the issue! I have connected a separate supply to the Pi and one to the screen, and now the network issue is fixed!
Jus need to sort the touch screen mapping issue out.
Any suggestions are welcome.