One-button dual monitor + peripherals switch: Mac ↔️ PC without KVM (LG USB-C DDC workaround, works with DualUp)
Full guide with scripts/configs: https://gist.github.com/vtalash/1ddc95746be08c0f2279424a65538b3e
My suggestion: feed this guilde to AI and ask him to explain and help to set up.
I wanted a true one-button switch for both monitors and all peripherals (keyboard, mouse, webcam, mic) between my Mac and PC.
I initially looked into KVM switches and contacted several manufacturers directly. The consistent answer: most likely incompatible with the LG DualUp (2560×2880 non-standard resolution) combined with MacBook Pro M1 USB-C limitations. Spending $800+ on a setup that probably wouldn't work didn't make much sense.
So I went the software/DDC route instead.
The main obstacle: LG hides USB-C input switching from standard DDC. VCP code 60 doesn't expose USB-C at all. Turns out it's controlled through a proprietary I²C side-channel at address 0x50. Once I figured that out, the rest became possible.
The guide includes:
- LG proprietary USB-C DDC switching
- Windows (NVIDIA) + Mac (Apple Silicon)
- AutoHotkey +
writeValueToDisplay.exe - Hammerspoon + BetterDisplay Pro
- wireless keyboard false-trigger prevention
- Karabiner-Elements remapping
- known edge cases and limitations
⚠️ Personal experiment — works on my setup, no guarantees for yours. I'll post a follow-up after a few weeks of stability testing. Feedback welcome.
⚠️ Guide and visualisation built by AI, so please do not judge