AMD GPUs now support DisplayPort 2.0
As reported by Phoronix, the latest patch notes for the Linux Kernel add preliminary support for DisplayPort 2.0 in AMD graphics drivers. Although the DisplayPort 2.0 standard was announced a few years ago, it was only in 2019 that official specifications were provided to all monitor manufacturers to allow this standard to be used in new models. As we reported a few months ago, unfortunately, due to the pandemic, monitors with DisplayPort 2.0 support have suffered significant delays; to date there are still no solutions on the market that integrate the new standard.The DP 2.0 continues to operate on 4 lines and allows you to take advantage of the UHBR (Ultra High Bit Rate) of 10, 13.5 or 20 Gbps per line, thanks to the transfer through passive copper cabling. Compared to the previous standard, DisplayPort 1.4, the amount of information that can pass inside the cable has significantly increased, allowing the passage of higher quality video streams.
Linux Kernel patch updates drivers for AMD GPU displays by adding support for UHBR 10, while UHBR 13.5 and 20 are not yet supported. UHBR is compatible with the VESA DisplayPort 8K (DP8K) certified standard which ensures resolutions such as 8K at 60Hz with HDR and 4K at 144Hz always with HDR.
The patch has therefore queued to be added to the drivers for AMD graphics cards, although we know it is targeted for the next generation of video cards, as the current RDNA2 architecture-based does not integrate DisplayPort 2.0 ports. The hope is that monitors equipped with the new standard will debut on the market as soon as possible, but it is likely that we will see them in conjunction with the arrival of future RDNA 3 GPUs.
AMD Posts Linux Patches In Preparing For DisplayPort 2.0 Radeon GPU Support
The latest feature display work to happen for the AMDGPU kernel driver since the debut of FreeSync HDMI in Linux 5.13 is around DisplayPort 2.0 support and specifically the SST UHBR10 handling.UHBR10 is one of the new data rates / modes of DisplayPort 2.0. With Ultra High Bit Rate (UHBR) 10 there is 10 Gbps per lane to allow 40 Gbps of bandwidth over passive copper cabling. The SST aspect of this patch series is just denoting it's for single stream transport rather than multi-stream transport (MST).
DisplayPort 2.0 additionally supports UHBR 13.5 and UHBR 20 modes but this patch series for the AMDGPU direct rendering manager driver is just in regards to the UHBR 10 mode. UHBR is compliant with VESA's DisplayPort 8K (DP8K) certification. Over DP HBR3, the UHBR 10 mode also allows for 4K @ 144Hz for standard video content and much broader support for HDR content at 4K and above at higher refresh rates than HBR3.
These six patches get the DP 2.0 SST UHBR10 support going after adding some five thousand lines of new code.
DisplayPort 2.0 was announced back in 2019 with a 3x increase to the data bandwidth performance, new power conservation features, and more. So far though the GPU hardware and driver support has been slow to materialize. Similarly, DisplayPort 2.0 monitors have been slow to reach market -- reportedly delayed by the pandemic but could begin appearing in the months ahead.
Due to the timing of these patches, however, it's not likely that they will get queued up for Linux 5.15 but more than likely divert to Linux 5.16. That though should ultimately be fine considering the latest-generation Radeon RX 6000 series supports DisplayPort 1.4. This AMDGPU DC work around DP 2.0 UHBR10 is likely in preparation for next-gen graphics (RDNA3 / Radeon RX 7000 series).