Orin specific Display Configuration

Update DCB blob for Custom Carrier Boards

Display Control Block (DCB) describes the display outputs and their configurations on a platform. Refer to https://download.nvidia.com/open-gpu-doc/DCB/2/DCB-4.x-Specification.html for more information about DCB.

The DCB blob is stored in platform specific dtsi files in the nvidia,dcb-image property under the display node. AGX Orin’s DCB blob is in the tegra234-dcb-p3701-0000-a02-p3737-0000-a01.dtsi file.

dcb_tool:

DCB blob is made up of hex values, which makes it difficult to decode/edit manually. dcb_tool helps parse DCB blob in dtsi file and also helps modify the values of the fields in the DCB blob. The dcb_tool is packaged in the <top>/Linux_for_Tegra/tools/dcb_tool/ directory.

Refer to the <top>/Linux_for_Tegra/tools/dcb_tool/readme.txt file for more information about the dcb_tool commands and their usage.

Note

To update the DCB blob, users need to reflash the Orin platform.

Display Device Tree Parameters

Refer to the <kernel-source-path>/nvidia/Documentation/devicetree/bindings/video/nvidia,tegra234-display.txt file from the source code for information about these parameters.

Changing the Display Function Between DP and HDMI

The Jetson Orin SOM provides DP or HDMI functionality. The pinmux sheet contains the tab for DP and HDMI. Depending on their custom carrier board design, end users should generate the appropriate pinmux files. In addition to pinmux changes, the kernel display dtsi files needs to be included in the carrier board kernel DT files, which contains DCB blob update to change between DP and HDMI Refer to Orin Display Configuration.

VT switching support

Default BSP:

  • Desktop GUI is enabled: VT switching not supported

  • If Desktop GUI is disabled: VT switching supported

Enable VT switching as a default option:

Update ''driver'' option in file ''/etc/X11/xorg.conf'' from ''nvidia'' to ''FBDev'' and reboot

Note

  1. Above procedure works only if desktop manager is ‘’X11’’ and not with ‘’Weston’’.

  2. Limitations of ‘’FBDev’’ driver:

    • Display is programmed by ‘’UEFI’’ hence supports features

    • ‘’SC7’’ feature does not work

    • ‘’Weston’’ apps does not work

Known Limitations

  • Seamless display: This feature will be supported in future releases for DP and HDMI.

  • Cannot switch between VT terminals when X11 is launched with Orin display drivers.

  • Killing the X11/Weston app launched with Orin display drivers will not return to VT terminal.