Hey everyone,
I’m looking into purchasing the new HDMI (4th Gen) Expansion Card when it is available. The spec sheet mentions support for HDMI 2.1a, DSC 1.2a, and up to 4K 240Hz output.
Since Framework mainboards output only native DisplayPort over USB-C (DP Alt Mode) and this card acts as an active Protocol Converter (PCON), I want to clarify how it handles FRL (Fixed Rate Link) and VRR in practice:
- FRL Lanes & Max Bandwidth: What is the exact configuration of the PCON chip used in the 4th Gen card? Does it support full 48Gbps (4 lanes at 12Gbps)? On which Framework models can it natively stream uncompressed 4K@120Hz (requires FRL), and on which Framework models does it rely on DSC?
- VRR over FRL Conversion: Active DP-to-HDMI conversion often drops VRR (Adaptive-Sync/FreeSync/G-Sync). If anyone successfully verifies VRR support at 4K@120+Hz using this specific 4th Gen card, please share it here.
- OS & Driver Stack: Given the historical HDMI Forum open-source limitations regarding FRL, how does this card behave under Linux? Does the PCON handle the FRL training internally so that the OS just sees a standard DP MST/SST target, or do we still need the latest upstream kernel patches (like Kernel 7.4+ AMD/Intel FRL updates) to it working in FRL mode with VRR?
Would love to hear from anyone who has tested this card when it is out or from the Framework team regarding the internal PCON chip specs and FRL & VRR compatibility with different Framework models.
Thank you in advance!