RustDesk — DRM/KMS Capture Fork

⚠️ This is an experimental fork of RustDesk with a DRM/KMS screen capture backend for Linux. An upstream PR is planned once AMD GPU testing is completed.

What's Different

This fork adds a DRM/KMS capture backend powered by libdrmtap, replacing PipeWire/portal-based capture on Linux. This means:

• No user consent popup — no "Select the screen to be shared" dialog
• Works on login screen — GDM, SDDM, LightDM
• Works headless — no display server needed
• Works in VMs — virtio-gpu, QEMU, cloud instances
• No PipeWire dependency — works on minimal systems
• Handles GPU tiling — Intel CCS, NVIDIA tiled, AMD automatically via EGL

The DRM backend is tried first; if it fails (e.g., no DRM device, or on X11 with proprietary drivers that don't expose CRTCs), it falls back to the standard PipeWire → X11 pipeline. No existing functionality is broken.

Tested Platforms

GPU	Driver	Resolution	Detiling	CPU (idle)	CPU (active)	Status
Intel Gen12 (Alder Lake)	i915	3840×2160	EGL (CCS)	~5%	~30%	✅ Working
NVIDIA Jetson Orin Nano	nvidia-drm 540.4.0	1920×1080	EGL (tiled)	8%	14%	✅ Working
virtio-gpu (QEMU/KVM)	virtio_gpu	1920×1080	None (linear)	~3%	~20%	✅ Working
AMD (amdgpu)	amdgpu	—	—	—	—	⏳ Pending

Performance Optimizations

The capture loop includes two key optimizations for low-power devices:

1. Rate limiter (16ms) — Caps capture at ~60 FPS, prevents CPU spinning
2. fb_id skip — Detects static screens by comparing framebuffer IDs, skipping expensive EGL detiling and memory copies when nothing changed

On the NVIDIA Jetson Orin Nano (6-core ARM, no hardware encoder), these brought CPU from 97% → 8% idle, 14% active.

Building (Linux)

Prerequisites

# Install libdrmtap
git clone https://github.com/fxd0h/libdrmtap
cd libdrmtap
meson setup build && meson compile -C build && sudo meson install -C build
sudo ldconfig

# Grant capture permissions (one of):
sudo setcap cap_sys_admin+ep /path/to/rustdesk    # Direct access
# OR install the drmtap-helper with setcap         # Helper binary

Build RustDesk

git clone https://github.com/fxd0h/rustdesk -b feature/drm-capture
cd rustdesk
cargo build --release --features linux-pkg-config

Environment Variables

Variable	Description	Example
DRM_DEVICE	Override DRM device path	/dev/dri/card1
DRMTAP_DEBUG	Enable debug logging	1

Changed Files

File	Change
libs/scrap/src/common/drm.rs	[NEW] DRM/KMS capture backend (inline FFI to libdrmtap)
libs/scrap/src/common/linux.rs	Added DRM variant, DRM-first fallback logic
libs/scrap/src/common/mod.rs	Added mod drm; declaration
libs/scrap/build.rs	Added libdrmtap link search paths

Upstream Status

• Open feature request issue on rustdesk/rustdesk
• AMD GPU testing
• Submit PR

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For the original RustDesk README, see upstream. libdrmtap is MIT licensed: github.com/fxd0h/libdrmtap