One of the first prototypes of Steam Machine, the Xi3 Piston mini-PC, was reviewed in detail on the Bringus Studios YouTube channel. This PC of 2013 runs Windows instead of the Linux-based SteamOS operating system. According to Bringus Studios’ tests, the PC that Xi3 later released under the name Piston has mediocre gaming performance, and even at the time it was not very fast.
The Xi3 Piston has an AMD Trinity processor and 8 GB of RAM. This chip is called R-464L, but it is actually an analog of the 2012 AMD A10-4600M. But the most interesting part of the computer can be seen not from the inside, but from the outside. This is a combined DisplayPort and HDMI connector.
So, after the video about the Xi3 Piston by Bringus Studios, a former Xi3 employee contacted the team on Discord and explained the purpose of the DP port with HDMI signal support (there is still no full pin compatibility). Experimenters have been changing the HDMI or DisplayPort settings in the BIOS, but the employee says that the default BIOS setting should automatically determine which device is connected.
Website PC Watch I took a closer look at the connector: it turned out to be a REGO Electronics HDMI/DisplayPort 2-in-1 model. It uses a non-standard 21st pin. When it’s free, the connection works like HDMI, while DisplayPort actually closes this pin and enables its own protocol. HDMI and DP plugs work great with this particular port and fit snugly, like «native».
The conventional HDMI and DP connectors are outright physically incompatible physically. The extra contact and elimination of some parts of the original connector helped create DisplayPort, which accepts the HDMI plug well. With the current status quo of video cards typically having 3 DP and one HDMI connectors and monitors being dominated by HDMI, motherboard and video adapter manufacturers could have benefited from this 13-year experience.
Source: Tom’s Hardware