Can't get waveshare 7" DSI screen to work

Rotil66 · February 19, 2025, 4:41pm

Edit:
Partly solved:
By editing the dtoverlay setting the screen started to work. Touch is detected but way off. Now calibration is not working.
Touch is detected.ntimer resets. but pocedure is not proceeding.
???

Hi All,
I have a running Zynthian setup. (worked with a hdmi 4.3 screen)
I just received a waveshare 7 inch DSI screen, but I can’t get it to work.
I have connected the DSI ribbon cable and the power SDA/SCL gpio cable.
But the screen is just black (on the back there is a green led blinking).
I can login the the web interface and I have selected the waveshare 7" dsi display (rebooted)
But still no picture. (Also tried the Generic dsi Display)
What am I doing wrong ??

Thanks

tunagenes · February 19, 2025, 4:56pm

have you tried both DSI connectors and rebooting with each ? I remember in some configurations only one of them works with Zynthian, I think this was on RPi5.

Rotil66 · February 19, 2025, 5:02pm

Both ??
On the PI4b there is only one Display connector. The other one is for a camera

tunagenes · February 19, 2025, 5:32pm

I guess this was only on RPi5.

hannesmenzel · February 19, 2025, 5:41pm

I didn’t ever worked with DSI screens, but did you connect power or SDA/SCL? I guess the latter have their connection with the DSI connection already.

Rotil66 · February 19, 2025, 5:42pm

I have found some dtoverlay setting and entered this in the web interface.
Now the screen is working
Now I have the problem that the touch is working but totally off…
now calibration is not working.
The calibration point is reacting to touch but the process is not proceeding (only the counter is resetting on touch.
Do I need to enter settings for this ???

le51 · February 19, 2025, 6:09pm

Hi

That’s strange because the settings looks good regarding waveshare’s wiki;

github.com/zynthian/zynthian-webconf

lib/display_config_handler.py

oram


      
              'overscan_left=8\n' +
              'overscan_right=8\n' +
              'overscan_top=0\n' +
              'overscan_bottom=0\n',
              'DISPLAY_WIDTH': '1920',
              'DISPLAY_HEIGHT': '1080',
              'DISPLAY_ROTATION': "None",
              'DISPLAY_KERNEL_OPTIONS': '',
              'FRAMEBUFFER': '/dev/fb0'
          },
          'WaveShare 5 or 7 DSI': {
              'DISPLAY_CONFIG':
                  'dtoverlay=vc4-kms-v3d,noaudio\n' +
                  'dtoverlay=vc4-kms-dsi-7inch\n',
              'DISPLAY_WIDTH': '800',
              'DISPLAY_HEIGHT': '480',
              'DISPLAY_ROTATION': "None",
              'DISPLAY_KERNEL_OPTIONS': '',
              'FRAMEBUFFER': '/dev/fb0'
          },
          'WaveShare 5 or 7 DSI (inverted)': {

good, so wich one is this overlay ?

For the touch function, there’s a dedicated paragraph in the waveshare wiki.

Rotil66 · February 19, 2025, 6:17pm

I selected the waveshare dsi 5/7 inch preset
and added this line

dtoverlay=vc4-kms-dsi-waveshare-panel,7_0_inchC,i2c1

Now I’m looking to get the touch working correctly. The info in the wiki page is a bit above my (newby) knowledge.
Any tips on this.

Rotil66 · February 19, 2025, 9:55pm

This can be closed.

I gave up on this screen it’s going to be returned.
Need advice fir a good working screen…

thanks