I built a desktop PC with a discrete Nvidia graphic card two years and half ago. A monitor has been connected to the PC, served my coding practice since then. While I started learning ROS 2 recently, one monitor seems inconvenient because many terminals are often needed to manipulate and inspect running nodes.
So I decided to buy one additional monitor and connect to the HDMI port of the integrated graphic card. However, the second monitor stayed black, and both Ubuntu and Windows 10 installed on the PC did not report any clue of the integrated graphic card. After searching on the Internet, I noticed someone questioned the BIOS’s necessity of disabling the integrated graphic card on PC with a discrete one.
Gotta! The problem is BIOS settings. For my GigaByte mainboard, I entered BIOS, went to Chipset tab, and found an Internal Graphic setting. I changed the setting from Auto to Enabled. After saving BIOS settings and rebooting, my second monitor worked as expected.
Also, there is another way to utilize additional monitors via DisplayPort and DVI ports on the discrete graphic card, as long as the monitors have such ports.