Documentation

One binary. The menu-bar app and the dsp command are the same executable, and installing puts a login item in place so the agent starts with your session.

Or build it yourself — it needs only the Xcode command line tools, no package manager and no Xcode project:

git clone https://github.com/deepakmarathe/display-upscale
cd display-upscale
./build.sh

./build.sh uninstall removes the login item, the app and the command, and keeps your settings.

A mode is 1:1when its framebuffer matches the panel's real pixel grid, and downscaled when the framebuffer is larger. Downscaled is always softer: the GPU renders more pixels than the panel has and then resamples them down, so every glyph edge lands between physical pixels.

This is why forcing "HiDPI" onto a native 1080p monitor makes text duller, not sharper — you trade a 1:1 pixel mapping for a bilinear blur, and there are no extra pixels to win. It is also why dsp override refuses to generate an EDID override for a panel macOS is already driving fully.

<index> is the bracketed number from dsp list, not a display ID.

Every dsp ddc write prints its own undo command with the previous value.

Diagnosis and manual fixes are free on every tier. Paid tiers automate them and add the hardware controls.

These numbers come from the same file the application reads, so this table cannot drift from what the binary enforces.

Every install starts with 14 days of Pro — no card, no account. When it ends the app returns to Free; nothing breaks and your displays stay where they are.

A licence is an Ed25519-signed token verified against a key compiled into the application. There is no licence server, so activation works offline and a provider outage cannot lock you out. Activate by clicking the link in your receipt, pasting the key into the menu-bar app, or:

dsp activate 'DU1.…'
dsp license          # what is active now
dsp deactivate       # release this Mac

The key is stored at ~/Library/Application Support/dsp/license.token and nowhere else.

A row appears here only when it has actually been run. "Should work" is not a support commitment.

macOS

• Supported
  macOS 26 (Tahoe)

  Developed and tested on this release.

• Supported
  macOS 15 (Sequoia)

  Same APIs; DDC path unchanged.

• Supported
  macOS 14 (Sonoma)

  Minimum for the private IOAVService DDC symbols to be present.

• Security fixes only
  macOS 13 (Ventura)

  Runs, and mode switching works. DDC is not exercised on this release — the app reports it as unavailable rather than guessing.

• End of life
  macOS 12 and earlier

  Below the build's deployment target; the app will not launch.

Hardware

• Supported
  Apple Silicon (M1–M5)

  The DDC path is written against Apple Silicon's IOAVService and is what all testing runs on.

• Security fixes only
  Intel Macs

  Mode listing, mode switching and the agent work. DDC uses a different IOKit path on Intel and is reported as unavailable rather than half-working.

• Supported
  Built-in Retina displays

  Detected as built-in; EDID overrides are refused for them by design.

• Supported
  External displays over DisplayPort / USB-C

  Including DDC, when the cable path passes I2C through.

• Supported
  Displays behind a hub or KVM

  Modes and the agent work. Many hubs do not pass I2C, so DDC may be unavailable — the app says so instead of failing silently.

Support window: the current minor release is supported, the one before it receives fixes for anything that blocks a launch or loses settings, and older releases are end of life. Small enough that we can actually honour it.

• 1.1.02026-08-04Supported
  • `dsp doctor` — one command that finds everything wrong with your displays, ranked, with the fix for each. Free on every tier.
  • Desk profiles: name the set of displays in front of you and every mode, brightness and contrast returns automatically when they reappear (Pro)
  • `dsp ddc all` sets every external display at once, and values accept +N / -N steps
  • Fixed: a DDC write did not wait the mandated 50ms before the next command, so the command after any write was silently dropped by the panel
• 1.0.02026-08-04Security fixes only
  • Menu-bar agent that keeps every managed display on its sharpest 1:1 mode
  • Pinned per-display profiles that survive sleep, replug and reboot
  • Monitor controls over DDC/CI — brightness, contrast, sharpness, colour
  • EDID override generation, refused for panels macOS already drives fully
  • Offline licence verification; Free, Pro and Studio tiers

Anything else: support@dfacto.ai, or open an issue on GitHub. We reply within 2 business days.