VESA steams ahead with DisplayPort 1.4a, allows for 8K scaling



The Video Electronics Standards Association (VESA) only published the updated DisplayPort 1.3a standard a few short months ago, but the organization has kept busy in the intervening months. Today, the new DisplayPort 1.4a embedded DisplayPort (eDP) standard was published. eDP replaces the eDP 1.4 standard that was published a year ago and contains a number of significant updates.

With eDP 1.4a, VESA is standardizing a number of features that were first introduced in DisplayPort 1.3. Like DP 1.3, 1.4a will use significantly faster signaling, with total capability of up to 8.1Gbps per lane. Embedded panels will be capable of up to 8K, thanks in part to the VESA DisplayStream Compression (DSC 1.1) standard. DSC was itself approved last year, and is a visually lossless codec that’s designed to reduce bandwidth pressure on next-gen devices while still allowing for improved resolution and scaling at reduced power envelopes.

The other new feature of eDP 1.4a is a feature VESA calls “Multi-SST operation” or MSO. MSO, in turn, can support a new type of display that VESA refers to as a “Segmented Panel Display.” An SPD display can be fed by a specific DisplayPort lane.



What this suggests, in aggregate, is that various areas of the display could be refreshed at different rates. The press release notes that:

Segmented Panel Display is designed to enable thinner, lighter and lower-cost panels that use less power. In operation, MSO allows the four high-speed eDP data lanes within the eDP interface to be divided up between either two or four independent panel segments. For lower resolutions, two lanes can be used to support two panel segments. This panel segmentation enables a higher level of integration on high-resolution displays; each segment can contain a separate timing controller with integrated source drivers.

This new feature was apparently proposed by Samsung, who believes it will reduce power consumption, screen thickness, and allow for greater display flexibility. It builds on the flexible display rate technologies that we’ve seen other vendors push, including Intel. The basic idea is that by controlling when a display updates and offering features that allow the display to drop into lower power modes, the total screen power consumption can be reduced. This is particularly important as CPUs hit lower process nodes and display resolutions rise — when you combine those trends, the end result is that screens are consuming an increasing percentage of total device power even as the CPU accounts for an ever-smaller amount.

As with DisplayPort 1.2a and 1.3, Adaptive-Sync is supported in embedded DisplayPort 1.4a but remains an optional part of the specification. That means we’ll likely see the technology confined to a relatively small set of panels and monitors and blocked off as a premium-access feature. The impact this will have on efforts to bring Adaptive-Sync and mobile G-Sync to laptops is unknown, but OEMs may be planning to use the capability as a useful value-add. One interesting note is that while eDP initially contained the capability that allowed AMD to discuss FreeSync as a potential G-Sync counter in the first place, Adaptive-Sync remains an optional part of the embedded DisplayPort 1.4a standard. This implies that Adaptive-Sync and the VLBANK feature used in eDP are not synonymous, and gives some credence to the idea that enabling full mobile G-Sync support isn’t as simple as flipping a switch.