Display Framebuffer Activity — But No Meaningful Output Yet

I’ve made some solid progress with the RGB display on the Nokia N97 cyberdeck, but I’m still running into issues. The good news: the screen is showing framebuffer activity. That means the display is powered, initialized, and receiving pixel data. I can see coloured lines and flickers that confirm data is reaching the panel. However, the output isn’t yet meaningful — no clear image or UI is appearing.

This usually means the hardware communication is mostly working, but something is off in the initialization sequence or timing. It could be an incorrect reset pulse, bad signal polarity, or an issue with the framebuffer colour format. Debugging this is tricky, so I’ve been capturing video to document what’s happening and get feedback from the community.

Prototyping on Full-Size Raspberry Pi, Moving to Compute Module 3+

For initial prototyping and testing, I used a full-size Raspberry Pi 3 Model B to quickly iterate on the display and software. Now that I’m moving closer to final integration, I’ve switched to the Raspberry Pi Compute Module 3+. The CM3+ offers a much smaller form factor and more flexible GPIO routing, making it a perfect fit for the cyberdeck’s compact chassis.

I’m updating the display initialization code and GPIO handling to match the Compute Module’s pinout, aiming to resolve the RGB panel communication issues and achieve a working display.

• link to screen video showing framebuffer activity.
• https://cdn.hackaday.io/files/2033918701880544/RGB_Framebuffer_active.mp4