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LG UltraGear 45GX950A (5K2K OLED): capability report + non-standard input VCP codes #1872

Description

@gmarmat

Capability report for the LG UltraGear 45GX950A (45" curved 5K2K OLED, released 2026). MonitorControl works on this monitor out of the box. Posting the details for the supported-displays list and for anyone searching for this model.

Setup

  • MacBook Pro M4 (Mac16,1), macOS 26.4.1
  • MonitorControl 4.3.3 (installed via Homebrew cask)
  • LG 45GX950A over USB-C / DisplayPort Alt Mode
  • DDC/CI enabled in the monitor OSD

What works

  • Brightness via F1/F2
  • Volume via F11/F12
  • Contrast slider in app preferences
  • Input source switching via m1ddc set input-alt <code>

Quirks worth documenting

Volume granularity. The 45GX950A exposes ~17 discrete DDC volume steps (~6% per step). The monitor's DDC firmware caps this. Same step size with m1ddc set volume, direct DDC writes, and other DDC-based apps. Not a MonitorControl issue, but worth mentioning if a user files "volume jumps in 6% increments" against this model.

Channel reporting. The monitor identifies as 8-channel over DisplayPort. Some apps (Microsoft Teams in particular) filter it out of their speaker dropdowns as a result. Unrelated to MonitorControl, listing for completeness.

Non-standard input VCP codes

The 45GX950A uses non-spec values for VCP 0x60 (input source). Confirmed by reading the current input via m1ddc input-alt while switching sources from the joystick:

Input VCP value (decimal)
USB-C / Thunderbolt 15
DisplayPort 1 208
DisplayPort 2 209
HDMI 1 144
HDMI 2 145

Spec values for DP1/DP2/HDMI1/HDMI2 are typically 15/16/17/18. The higher values may apply to other 2026 LG OLED UltraGear models. If anyone on a recent LG hits input-switch failures with the standard codes, these are worth trying.

Happy to test additional VCP codes if useful.

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