nanoDLP

Rahul

Member

Registered: 2019-11-27

Posts: 39

Struggling with MIPI display issues

Hello,

I have an LCD display connected to Rpi4 through HDMI-MIPI converter board. However, for some reason as soon as NanoDLP service triggers, the display is no longer connected and blue LED flashes on MIPI converter board.

Observations:
1. When Rpi is booting the display is detected and there is a green light on the MIPI converter board and the display is working as expected
2. But as soon as nanodlp service starts, the display is no longer connected and blue led flashes on mipi board.
3. To test this further, I disabled nanodlp.service and the display continued to work fine.

Looks like there is something wrong happening when nanodlp start which kicks out the display. Any pointers will help.

thanks!!
R

Shahin

Administrator

Registered: 2016-02-17

Posts: 3,546

Re: Struggling with MIPI display issues

Hi Rahul,

Try framebuffer see if it does improve things or not.

Rahul

Member

Registered: 2019-11-27

Posts: 39

Re: Struggling with MIPI display issues

Hello Shahin,
Was able to resolve the display issue. However, the display seems to be noisy, the calibration grids keeps jumping and even when print layers are previewed on display some stray pixels keep glowing.

I have recorded are small video to depict the issue. Link: https://drive.google.com/file/d/1wa1bav … sp=sharing

My Setup:
Rpi4 with nanoDLP build 7267 with 2K RGB 5.5" LCD

config.txt:
hdmi_pixel_encoding:0=2
hdmi_force_mode:0=1

hdmi_cvt:0=1440 2560 50 3 0 0 0

hdmi_group:0=2
hdmi_mode:0=87
hdmi_drive:0=2
hdmi_force_hotplug:0=1
config_hdmi_boost:0=4

framebuffer_width:0=1440
framebuffer_height:0=2560
max_framebuffer_width:0=1440
max_framebuffer_height:0=2560

Tried replacing Rpi, mipi converter board, and displays but the issue seems consistent. Any suggestion on fixing this.

thanks!

Shahin

Administrator

Registered: 2016-02-17

Posts: 3,546

Re: Struggling with MIPI display issues

Check if your display config exists here and correct.
https://docs.google.com/spreadsheets/d/ … gp5Vk/edit

SiPowell1986

Member

Registered: 2024-07-07

Posts: 6

Re: Struggling with MIPI display issues

Are you using an ls055r1sx04?

# DISPLAY SETTINGS
gpu_mem=192
hdmi_force_hotplug=1
hdmi_timings=1440 0 50 10 35 2560 0 4 2 2 0 0 0 50 0 198000000 0
hdmi_group=2
hdmi_mode=87
hdmi_pixel_freq_limit=500000000
hvs_priority=0x32ff
display_rotate=0x10000
max_framebuffer_width=1440
max_framebuffer_height=2560
framebuffer_width=1440
framebuffer_height=2560
framebuffer_depth=24
framebuffer_ignore_alpha=1
config_hdmi_boost=2

Mine are working with the above display settings, using build 8883