Table of Contents
|Table of Contents
Installing a Graphical Package Manager
The core of the Ubuntu ecosystem is 3rd-party packages. Ubuntu 20.04 LTS provides some packages as tradition Debian
.deb packages in apt repositories. Sandboxed modern applications are provided as Snaps (such as
xlnx-config). By default, the Certified Ubuntu on Xilinx Devices image does not provide a graphical package manager. If you would like to add one, there are several available in the existing Ubuntu package repository ecosystem.
$ sudo snap install snap-store
Stopping the Ubuntu Graphical Desktop Environment
If you wish to stop the Ubuntu graphical desktop environment and return to a strictly command line environment, you can do so by using the
systemd interfaces. The
systemd “multi-user” target is equivalent to runlevels 3, 4, or 5 in traditional systems based on
SysVInit. This can be used to save system memory which would otherwise be used for running the rich desktop experience.
$ sudo systemctl enable multi-user.target $ sudo systemctl set-default multi-user.target
Switching Desktop Environments
The default graphical environment in Ubuntu 20.04 LTS is based on GNOME3. Other desktop environments are available and can be installed to suit personal preference.
NOTE: The default Ubuntu display manager is
Screen Sharing and VNC
You can share the desktop by enabling Screen Sharing in the GNOME desktop settings. You first need to install the Vino package. More details can be found at the following page:
Understanding CMA Usage
Many of the Xilinx designs, particularly those that leverage the Xilinx Video Codec Unit (VCU), make extensive use of Contiguous Memory Allocator (CMA) in the Linux kernel.
For general usage, Xilinx does not recommend lowering the CMA below 256MB
Updating the Board-Level Metadata EEPROM
Xilinx evaluation boards have metadata about the board stored in an I2C EEPROM soldered to the board. Among this data is the serial number of the board, name of the board (eg, ZCU102), board revision, and Ethernet MAC address.
Xilinx declares how & where this information is stored in the device tree DTS file for the ZCU102 here: https://raw.githubusercontent.com/Xilinx/u-boot-xlnx/master/arch/arm/dts/zynqmp-zcu102-rev1.0.dts
The same basic process can be used to update the Board Name, Board Serial Number, or Board Version fields. Keep in mind that when writing the values for the Board Name, Board Version Number, and Board Serial Number to use the ASCII values in hexadecimal. The MAC address is written in native hexadecimal values.
Ubuntu Internal Error Messages
From time to time, the Ubuntu desktop may display error messages similar to Sorry, Ubuntu 20.04 has experienced an internal error.
$ sudo systemctl disable apport.service
Rebuilding the Image Selector Utility
The core of the Certified Ubuntu for Xilinx Devices boot process on ZCU10x boards is the Image Selector tool. This utility performs the initial boot of the board, reads board-identifying information from the attached EEPROM, and then reboots into a customized set of boot collateral for the specific board it is running on. For more detail on this process, see the Booting Certified Ubuntu for Xilinx Devices page.This is what allows the same Certified Ubuntu for Xilinx Devices SD card image to boot on multiple boards. Typically, there is no need to modify this code. If a user determines that they would like to modify the way that Image Selector operates, it can be rebuilt inside the Vitis environment. The source code of Image Selector is part of the Xilinx
embeddedsw repository on the Xilinx GitHub.
Using a Custom Device Tree
To temporarily override the dtb without modifying the fit image (Kria) or bootxxxx.bin (zcu10x), you can create a new dtb named "user-override.dtb". Copy user-override.dtb to the FAT partition and reboot. If user-override.dtb is found on the FAT partition by U-boot, it will use this dtb instead of the board-specific dtb found in the FIT image when Linux is started.
Configuring flash-kernel Prompts When Updating the Linux Kernel
When updating the Linux kernel via packages available in the Ubuntu package feed, the following prompt may appear: