DisplayPort


DisplayPort is a digital interface used to connect a video source, such as a computer, to a display device like a monitor. Developed by the Video Electronics Standards Association, it can also carry digital audio, USB, and other types of data over a single cable.
Introduced in the 2000s, DisplayPort was designed to replace older standards like VGA, DVI, and FPD-Link. While not directly compatible with these formats, adapters are available for connecting to HDMI, DVI, VGA, and other interfaces.
Unlike older interfaces, DisplayPort uses packet-based transmission, similar to how data is sent over USB or Ethernet. The design enables support for high resolutions and adding new features without changing the connector.
DisplayPort includes an auxiliary data channel used for device control and automatic configuration between source and display devices. It supports standards such as Display Data Channel, Extended Display Identification Data, Monitor Control Command Set, and VESA Display Power Management Signaling. Some implementations also support Consumer Electronics Control, which allows devices to send commands to each other and be operated using a single remote control.

Versions

1.0 to 1.1

The first version, 1.0, was approved by VESA on 3 May 2006. Version 1.1 was ratified on 2 April 2007, and version 1.1a on 11 January 2008.
DisplayPort 1.0–1.1a allow a maximum bandwidth of 10.8Gbit/s over a standard 4-lane main link. DisplayPort cables up to 2 meters in length are required to support the full 10.8Gbit/s bandwidth. DisplayPort 1.1 allows devices to implement alternative link layers such as fiber optic, allowing a much longer reach between source and display without signal degradation, although alternative implementations are not standardized. It also includes HDCP in addition to DisplayPort Content Protection. The DisplayPort1.1a standard can be downloaded free of charge from the VESA website.

1.2

DisplayPort version 1.2 was introduced on 7 January 2010. The most significant improvement of this version is the doubling of the data rate to 17.28Gbit/s in High Bit Rate 2 mode, which allows increased resolutions, higher refresh rates, and greater color depth, such as at 60Hz 10bpc RGB. Other improvements include multiple independent video streams called Multi-Stream Transport, facilities for stereoscopic 3D, increased AUX channel bandwidth, more color spaces including xvYCC, scRGB, and Adobe RGB 1998, and Global Time Code for sub 1μs audio/video synchronisation. Also Apple Inc.'s Mini DisplayPort connector, which is much smaller and designed for laptop computers and other small devices, is compatible with the new standard.

1.2a

DisplayPort version 1.2a was released in January 2013 and may optionally include VESA's Adaptive Sync. AMD's FreeSync uses the DisplayPort Adaptive-Sync feature for operation. FreeSync was first demonstrated at CES 2014 on a Toshiba Satellite laptop by making use of the Panel-Self-Refresh feature from the Embedded DisplayPort standard, and after a proposal from AMD, VESA later adapted the Panel-Self-Refresh feature for use in standalone displays and added it as an optional feature of the main DisplayPort standard under the name "Adaptive-Sync" in version 1.2a. As it is an optional feature, support for Adaptive-Sync is not required for a display to be DisplayPort 1.2a-compliant.

1.3

DisplayPort version 1.3 was approved on 15 September 2014. This standard increases overall transmission bandwidth to 32.4Gbit/s with the new HBR3 mode featuring 8.1Gbit/s per lane, for a total data throughput of 25.92Gbit/s after factoring in 8b/10b encoding overhead. This bandwidth is enough for a 4K UHD display at 120Hz with 24bit/px RGB color, a 5K display at 60Hz with 30bit/px RGB color, or an 8K UHD display at 30Hz with 24bit/px RGB color. Using Multi-Stream Transport, a DisplayPort port can drive two 4K UHD displays at 60Hz, or up to four WQXGA displays at 60Hz with 24bit/px RGB color. The new standard includes mandatory [|Dual-mode] for DVI and HDMI adapters, implementing the HDMI2.0 standard and HDCP2.2 content protection. The Thunderbolt 3 connection standard was originally to include DisplayPort1.3 capability, but the final release ended up with only version 1.2 for Intel 6000 Series Thunderbolt 3 Controllers. Later Intel 7000 Series Thunderbolt 3 controllers support DisplayPort1.4 capability including HDR. The VESA's Adaptive Sync feature in DisplayPort version 1.3 remains an optional part of the specification.

1.4

DisplayPort version 1.4 was published 1 March 2016. No new transmission modes are defined, so HBR3 as introduced in version 1.3 still remains as the highest available mode. DisplayPort1.4 adds support for Display Stream Compression 1.2, Forward Error Correction, HDR10 metadata defined in CTA-861.3, including static and dynamic metadata and the Rec. 2020 color space, for HDMI interoperability, and extends the maximum number of inline audio channels to 32.

1.4a

DisplayPort version 1.4a was published in April 2018. VESA made no official press release for this version. It updated DisplayPort's Display Stream Compression implementation from DSC 1.2 to 1.2a.

2.0

On 26 June 2019, VESA formally released the DisplayPort 2.0 standard.
VESA stated that version 2.0 is the first major update to the DisplayPort standard since March 2016, and provides up to a ≈3× improvement in data rate compared to the previous version of DisplayPort, as well as new capabilities to address the future performance requirements of traditional displays. These include beyond 8K resolutions, higher refresh rates and high dynamic range support at higher resolutions, improved support for multiple display configurations, as well as improved user experience with augmented/virtual reality displays, including support for 4K-and-beyond VR resolutions.
According to a roadmap published by VESA in September 2016, a new version of DisplayPort was intended to be launched in "early 2017". It would have improved the link rate from 8.1 to 10.0Gbit/s, a 23% increase. This would have increased the total bandwidth from 32.4Gbit/s to 40.0Gbit/s. However, no new version was released in 2017, likely delayed to make further improvements after the HDMI Forum announced in January 2017 that their next standard would offer up to 48Gbit/s of bandwidth. According to a press release on 3 January 2018, "VESA is also currently engaged with its members in the development of the next DisplayPort standard generation, with plans to increase the data rate enabled by DisplayPort by two-fold and beyond. VESA plans to publish this update within the next 18 months." At CES 2019, VESA announced that the new version would support 8K @ 60Hz without compression and was expected to be released in the first half of 2019.

DP 2.0 configuration examples

With the increased bandwidth enabled by DisplayPort 2.0, VESA offers a high degree of versatility and configurations for higher display resolutions and refresh rates. In addition to the above-mentioned 8K resolution at 60Hz with HDR support, DP 2.0 through USB-C as DisplayPort Alt Mode enables a variety of high-performance configurations:
  • Single display resolutions
  • * One 16K display @ 60Hz with 10bpc RGB/ 4:4:4 color
  • * One 10K display @ 60Hz and 8bpc RGB/ 4:4:4 color
  • Dual display resolutions
  • * Two 8K displays @ 120Hz and 10bpc RGB/ 4:4:4 color
  • * Two 4K displays @ 144Hz and 8bpc RGB/ 4:4:4 color
  • Triple display resolutions
  • * Three 10K displays @ 60Hz and 10bpc RGB/ 4:4:4 color
  • * Three 4K displays @ 90Hz and 10bpc RGB/ 4:4:4 color
When using only two lanes on the USB-C connector via DP Alt Mode to allow for simultaneous SuperSpeed USB data and video, DP 2.0 can enable such configurations as:
  • Three 4K displays @ 144Hz and 10bpc RGB/ 4:4:4 color
  • Two 4K × 4K displays @ 120Hz and 10bpc RGB/ 4:4:4 color
  • Three QHD @ 120Hz and 8bpc RGB/ 4:4:4 color
  • One 8K display @ 30Hz and 10bpc RGB/ 4:4:4 color

    2.1

VESA announced version 2.1 of the DisplayPort standard on 17 October 2022. This version incorporates the new DP40 and DP80 cable certifications, which test DisplayPort cables for proper operation at the UHBR10 and UHBR20 speeds introduced in version 2.0. Additionally, it revises some of the electrical requirements for DisplayPort devices in order to improve integration with USB4. In VESA's words:

DisplayPort 2.1 has tightened its alignment with the USB Type-C specification as well as the USB4 PHY specification to facilitate a common PHY servicing both DisplayPort and USB4. In addition, DisplayPort 2.1 has added a new DisplayPort bandwidth management feature to enable DisplayPort tunnelling to coexist with other data traffic more efficiently over the USB4 link.

2.1a

VESA announced version 2.1a of the DisplayPort standard on 8 January 2024. This version replaces the DP40 cable certification with the new DP54 certification, which tests DisplayPort cables for proper operation at the UHBR13.5 speed introduced in version 2.0.

2.1b

VESA announced version 2.1b of the DisplayPort standard on 6 January 2025. It has been released in Spring 2025.

Specifications

Main

Main link

The DisplayPort main link is used for transmission of video and audio. The main link consists of a number of unidirectional serial data channels which operate concurrently, called lanes. A standard DisplayPort connection has 4 lanes, though some applications of DisplayPort implement more, such as the Thunderbolt 3 interface which implements up to 8 lanes of DisplayPort.
In a standard DisplayPort connection, each lane has a dedicated set of twisted-pair wires, and transmits data across it using differential signaling. This is a self-clocking system, so no dedicated clock signal channel is necessary. Unlike DVI and HDMI, which vary their transmission speed to the exact rate required for the specific video format, DisplayPort only operates at a few specific speeds; any excess bits in the transmission are filled with "stuffing symbols".
In DisplayPort versions 1.01.4a, the data is encoded using ANSI 8b/10b encoding prior to transmission. With this scheme, only 8 out of every 10 transmitted bits represent data; the extra bits are used for DC balancing. As a result, the rate at which data can be transmitted is only 80% of the physical bitrate. The transmission speeds are also sometimes expressed in terms of the "Link Symbol Rate", which is the rate at which these 8b/10b-encoded symbols are transmitted. The following transmission modes are defined in version 1.01.4a:
  • RBR : 1.62Gbit/s bandwidth per lane
  • HBR : 2.70Gbit/s bandwidth per lane
  • HBR2 : 5.40Gbit/s bandwidth per lane, introduced in DP1.2
  • HBR3 : 8.10Gbit/s bandwidth per lane, introduced in DP1.3
DisplayPort 2.0 uses 128b/132b encoding; each group of 132 transmitted bits represents 128 bits of data. This scheme has an efficiency of 96.%. In addition, a small amount of overhead is added for the link layer control packet and other miscellaneous operations, resulting in an overall efficiency of ≈96.7%. The following transmission modes are added in DP 2.0:
  • UHBR 10 : 10.0Gbit/s bandwidth per lane
  • UHBR 13.5 : 13.5Gbit/s bandwidth per lane
  • UHBR 20 : 20.0Gbit/s bandwidth per lane
The total bandwidth of the main link in a standard 4-lane connection is the aggregate of all lanes:
  • RBR: 4 × 1.62Gbit/s = 6.48Gbit/s bandwidth
  • HBR: 4 × 2.70Gbit/s = 10.80Gbit/s bandwidth
  • HBR2: 4 × 5.40Gbit/s = 21.60Gbit/s bandwidth
  • HBR3: 4 × 8.10Gbit/s = 32.40Gbit/s bandwidth
  • UHBR 10: 4 × 10.0Gbit/s = 40.00Gbit/s bandwidth
  • UHBR 13.5: 4 × 13.5Gbit/s = 54.00Gbit/s bandwidth
  • UHBR 20: 4 × 20.0Gbit/s = 80.00Gbit/s bandwidth
The transmission mode used by the DisplayPort main link is negotiated by the source and sink device when a connection is made, through a process called Link Training. This process determines the maximum possible speed of the connection. If the quality of the DisplayPort cable is insufficient to reliably handle HBR2 speeds for example, the DisplayPort devices will detect this and switch down to a lower mode to maintain a stable connection. The link can be re-negotiated at any time if a loss of synchronization is detected.
Audio data is transmitted across the main link during the video blanking intervals.