New DisplayPort specification

[bigbluefe]

http://www.vesa.org/featured-articles/vesa-publishes-embedded-displayport-edp-standard-version-1-4a/

 

[EdZ]

That's embedded DisplayPort, which brings eDP up to the bandwidth of DP1.3 (released last year). This is not a standard of interest to you unless you manufacture self-contained hardware (laptops and tablets).

 

[Later]

Sure this is of interest. As monitors move towards higher resolutions like 4k and beyond, more and more panels are adopting eDP interface. I wonder if we ever see Panel Self Refresh feature and its partial update capability introduced in eDP 1.4 standard used in monitors.

 

[EdZ]

I wonder if we ever see Panel Self Refresh feature and its partial update capability introduced in eDP 1.4 standard used in monitors.

DP Adaptive Sync (AKA AMD FreeSync on the client side) is a modification of Panel Self Refresh's asynchronous updating. Zone updating is a power saving feature, so probably won't end up in desktop monitors. The bandwidth-saving side-effects of partial refresh will probably be ignored in favour of stream compression and/or chroma subsampling.

 

[Later]

Partial update capability would benefit those who wish to attach their monitor to a laptop or tablet or maybe even smart phone one day. I would expect them to become majority of users in not so distant future and desktop PCs slowly die away. Even if you don’t agree with this scenario all power saving features would be welcome for portable device users.

 

[Later]

Forget about eDP 1.4a, VESA has published eDP 1.4b standard. It looks like IC suppliers have been waiting for this release that according to VESA “finalizes standard with protocol refinements that improve ecosystem interoperability and shorten time to market while maintaining high performance” and are skipping the launch of chips designed to earlier versions eDP 1.4 and eDP 1.4a. At least Parade, coinciding with the eDP 1.4b release, has announced two TCON devices that comply with the eDP 1.4b standard, the DP691 and the DP693. They only seem to feature 1.62 and 2.7 Gbps link rates instead of 8.1 Gbps high-speed HBR3 lanes the standard specifies however.

Changes seem to be made to make devices simpler to design and cheaper to manufacture. The most interesting bit was probably in the last paragraph of the announcement, with info regarding availability and a mention of DisplayPort 1.4:

By mid-2016, systems will begin to incorporate eDP 1.4b, and the final standard should continue to increase in adoption and be used in production for several years. In the meantime, VESA members will begin discussing plans for eDP 1.5, which will take advantage of new features that will be introduced in the future release of DisplayPort 1.4.

 

[Later]

VESA has published DisplayPort 1.4. The main feature seems to be to take advantage of Display Stream Compression (DSC) 1.2, which was released earlier this year and is a compression standard developed, unlike the previous version 1.1, to support monitors and televisions. The changes listed in a comparison table are support for 14 and 16 bits per color and native 4:2:0 and 4:2:2 coding.

According to this table DSC 1.2 will allow resolutions as high as 7680x4320@60Hz with 10 bpc using the 8.1 Gbit/s link rate DisplayPort 1.3 provides. VESA claims that DSC is visually lossless which DSC FAQ elaborates. How good that is for different use cases remains to be seen, but for gaming monitors this is surely a boon, as the FAQ also states that the decoder (at least for DSC 1.1) "adds no more than one raster scan line (less than 8 usec in a 4K @ 60Hz system) to the display’s throughput latency", and whatever slight loss in quality a compression might incur is offset and then some by the benefits a higher refresh rate offers. Especially as I reckon we will start to see DisplayPort 1.4 capable devices in 2018, exactly the year much more OLED capacity should go online and panels thus become more common and affordable, and OLED panels are not limited by pixel response times so they are inherently capable of high refresh rates as long as their Tcon supports DSC and has required bandwidth.