Debian on JWS3288 (RK3288) - LCD stays black, everything else works

Chip Platform Rockchip
1

Type: Official Firmware
Filename: JWS3288_Debian10_LVDS_231108
Download Address: JWS3288_Debian10_LVDS_231108
Log: JWS3288I.zip

Hi everyone,

I have a JWS3288 industrial board (Rockchip RK3288). It originally ran Android with the LCD working fine. I installed Debian 10 (image RK3288-Debian10-20231108.095729.img) using RKDevTool.

Everything works: SSH, network, Wi-Fi. But the LCD stays completely black, no backlight visible.

In software everything looks OK:

  • /dev/fb0 exists (1024x768) and accepts writes
  • DRM binds correctly (VOP + LVDS)
  • Backlight sysfs reports bl_power=0, brightness=255
  • LCD regulators are enabled

But physically the panel is off. Writing to /dev/fb0 shows nothing, not even a faint image with a flashlight.

My guess: the DTB in this Debian image is generic (probably Firefly-RK3288) and doesn’t match the actual panel/backlight GPIO/PWM mapping of the JWS3288.

Has anyone gotten Debian working on a similar industrial RK3288 board? Any tips on how to extract or adapt the DTB from the original Android ROM?

Thanks!

tchip_askquestions
JWS3288I.zip (1.29 MB)

2

Have you checked the display connector and the backlight driver? On Rockchip boards running Debian, the LCD backlight is often controlled by a PWM GPIO that needs to be explicitly enabled in the device tree. Try running cat /sys/class/backlight/brightness to see if the backlight node exists — if it does, writing a non-zero value should turn it on.