AMDISPLAY(4) - Device Drivers Manual (armv7) #

AMDISPLAY(4) - Device Drivers Manual (armv7)

NAME #

amdisplay, nxphdmi - Texas Instruments AM335x LCD display driver

SYNOPSIS #

amdisplay* at simplebus0
nxphdmi* at iic*‌
wsdisplay* at amdisplay*‌

DESCRIPTION #

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.

SEE ALSO #

intro(4), wsdisplay(4), wsfb(4)

HISTORY #

The amdisplay driver first appeared in OpenBSD 6.2.

AUTHORS #

The amdisplay driver was written by Ian Sutton <ians@openbsd.org>. The nxphdmi driver was written by Oleksandr Tymoshenko <gonzo@freebsd.org> and later ported to OpenBSD.

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.

OpenBSD 7.5 - May 29, 2019