---
name: "mgx"
section: "4"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["openbsd"]
url: "https://new.carta.tech/mgx"
---

# mgx(4)

SMS MGX and MGXPlus accelerated 8/24-bit color frame buffers

## NAME

**mgx** – SMS MGX and MGXPlus accelerated 8/24-bit color frame buffers

## SYNOPSIS

**mgx\* at sbus?** **wsdisplay\* at mgx?**

## DESCRIPTION

The Southland Media Systems (now Quantum 3D) MGX and MGXPlus are SBus color frame buffers, with graphics acceleration capabilities.

The **mgx** driver interfaces the frame buffer with the [wscons(4)](/wscons/4.md) console framework. It does not provide direct device driver entry points but makes its functions available via the internal [wsdisplay(4)](/wsdisplay/4.md) interface.

## DISPLAY RESOLUTION

The MGX and MGXPlus frame buffers will adapt their resolution to the monitor they are connected to. However, when not connected to a Sun monitor, the device will default to the [cgthree(4)](/cgthree/4.md)-compatible 1152x900 resolution, with a refresh rate of 66Hz. A different resolution can be forced using the set of DIP switches (sometimes covered by metal foil) located near the SBus connector on the board itself.

The DIP switch settings are as follows:

| | | | |
| --- | --- | --- | --- |
| **Switches** | **Resolution** | **Refresh Rate** | **Details** |
| **1 2 3 4** |  |  |  |
| OFF OFF OFF OFF | 1024x768 | 77Hz |  |
| OFF ON OFF OFF | 1280x1024 | 76Hz |  |
| ON ON OFF OFF | 1152x900 | 66Hz |  |
| OFF OFF ON OFF | 1152x900 | 76Hz |  |
| OFF ON ON OFF | 1152x900 | 77Hz |  |
| ON ON ON OFF | 1152x900 | 66Hz | cgthree compatible |
| ON ON OFF ON | 1152x900 | 66Hz | cgsix compatible |
| OFF OFF ON ON | 1280x1024 | 67Hz |  |
| ON ON ON ON | probed | probed | factory default |

All other combinations are unsupported and may damage the hardware.

## SEE ALSO

[intro(4)](/intro/4.md), [sbus(4)](/sbus/4.md), [wscons(4)](/wscons/4.md), [wsdisplay(4)](/wsdisplay/4.md)

## CAVEATS

This driver does not support mode switching at the moment, and drives the card in PROM-compatible, 8 bit, mode only.