amdisplay(4)

amdisplay4

Texas instruments am335x lcd display driver

Usage

amdisplay* at fdt? nxphdmi* at iic? wsdisplay* at amdisplay?

Overview

The amdisplay driver supports the LCD controller integrated in Texas Instruments' line of AM335x SoCs. The LCDC reads a framebuffer from memory via DMA and scans it out at the proper frequency to suit a display (along with the necessary hsync/vsync/etc. signals) to a PHY transmitter. The BeagleBone Black uses NXP/Freescale's TDA19988 HDMI transmitter, which is additionally supported by the nxphdmi driver.

Caveats

On the BeagleBone Black, the LCDC and onboard eMMC NAND chip share the same set of pads such that only one can be wired and used at a time. To boot from or use the onboard storage, disable amdisplay via config(8) in the kernel.

A display must be attached at boot time, otherwise amdisplay will fail to configure.

Hotplugging is not supported.

Only 16-bit color depth is supported due to a silicon bug.

History

The amdisplay driver first appeared in OpenBSD 6.2.

Authors

The amdisplay driver was written by Ian Sutton ⟨[email protected]⟩. The nxphdmi driver was written by Oleksandr Tymoshenko ⟨[email protected]⟩ and later ported to OpenBSD.

From man 8.0-current-20261101 in OpenBSD 8.0-current (2026-11-01). Parsed by carta from the page's mdoc source.