Display Port 1.4 to HDMI 2.1 (CAC 1085) and how to

0 on 22-06-2021

This piece of HW works on premise that..

  1. you have GPU with DP1.4 + DSC 1.2 and it works
  2. other side is TV/LCD with HDMI 2.1 with DSC and it works

 

Problems are these.

1. more often than not, GPUs have DP1.4 but without any form of DSC (super new ones that nearly nobody can buy do have DSC ofc)

2. GPUs (especially one in AMD APUs) have bastardized version of DSC thats absolutely non-compatible with everything else

3. TV actually doesnt have DSC, despite claming it has (rare)

Solution.

Firmware for CAC-1085 that would disable DSC in adapter and signalized both sides (TV/LCD and GPU) that there is no DSC on both sides (no matter if true or not).

What it would do in theory?

Result should be working DP1.4 to HDMI2.1 on basically everything that can more or less fit in those specs. It ofc means speed would be limited to around 32.40 Gbps which is DP1.4 limit, but look at it this way. Either you have adapter that doesnt work or you have adapter that gives you 32 Gbps, which is still quite a bit above HDMI 2.0 and thus you can use more resolutions/freq/bit depths.

Preferable way would be either firmware flash, or firmware switch. I think both is doable, but I dont really care how, just if it works.

Thats all.

 
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