Linux-DRM-Explorer

A systematic exploration of the Linux DRM/KMS subsystem on the Rockchip RK3588 (VOP2) platform. This project documents the complete display bring-up process, from low-level register verification to high-level atomic synchronization.

Key Project Highlights

• Cross-Subsystem Mental Model: Leveraging experience from Linux ASoC to master the DRM pipeline (Mapping DMA/Mixers to CRTC/Planes).
• Hardware-Level Debugging: Direct verification of Video Timing and Pixel Clocks via debugfs and hardware registers.
• Sync & Performance: Deep dive into dma-fence mechanisms and VBlank IRQ monitoring for smooth page-flipping.

Technical Experiments (Step-by-Step)

I have documented the bring-up process in 6 structured experiments:

1. KMS Pipeline Mapping: Analyzing internal resources (VP0-VP3) and Plane constraints.
2. Modetest mastery: Hands-on with atomic modesetting and troubleshooting object IDs.
3. DSI Panel Bring-up: Calculating Video Timings and verifying PCLK registers.
4. DRM Master Concepts: Understanding ownership conflicts between fbcon and userspace clients.
5. Composition & Sync: Hardware layering (Z-order) and the role of GEM/Fence.
6. VBlank & Page Flip: Real-time monitoring of VOP interrupts to verify display "heartbeat."
7. User Space Example: Implementing Userspace KMS using C and libdrm

Tools & Environment

• Hardware: LubanCat 5 (Rockchip RK3588)
• OS: Ubuntu Lite (Minimal environment for cleaner DRM debugging)
• Kernel Tools: modetest, debugfs, procfs, GICv3 interrupt controller analysis.

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Signed-off-by: TomHsieh300 hungen3108@gmail.com