[PATCH v4 00/16] Add support for DP-HDMI2.1 PCON

[Jani Nikula]

On Tue, 08 Dec 2020, Ankit Nautiyal <ankit.k.nautiyal at intel.com> wrote:
> This patch series attempts to add support for a DP-HDMI2.1 Protocol
> Convertor. The VESA spec for the HDMI2.1 PCON are proposed in Errata
> E5 to DisplayPort_v2.0:
> https://vesa.org/join-vesamemberships/member-downloads/?action=stamp&fileid=42299
> The details are mentioned in:
> VESA DP-to-HDMI PCON Specification Standalone Document
> https://groups.vesa.org/wg/DP/document/15651
>
> This series starts with adding support for FRL (Fixed Rate Link)
> Training between the PCON and HDMI2.1 sink.
> As per HDMI2.1 specification, a new data-channel or lane is added in
> FRL mode, by repurposing the TMDS clock Channel. Through FRL, higher
> bit-rate can be supported, ie. up to 12 Gbps/lane (48 Gbps over 4
> lanes).
>
> With these patches, the HDMI2.1 PCON can be configured to achieve FRL
> training based on the maximum FRL rate supported by the panel, source
> and the PCON.
> The approach is to add the support for FRL training between PCON and
> HDMI2.1 sink and gradually add other blocks for supporting higher
> resolutions and other HDMI2.1 features, that can be supported by pcon
> for the sources that do not natively support HDMI2.1.
>
> This is done before the DP Link training between the source and PCON
> is started. In case of FRL training is not achieved, the PCON will
> work in the regular TMDS mode, without HDMI2.1 feature support.
> Any interruption in FRL training between the PCON and HDMI2.1 sink is
> notified through IRQ_HPD. On receiving the IRQ_HPD the concerned DPCD
> registers are read and FRL training is re-attempted.
>
> Currently, we have tested the FRL training and are able to enable 4K
> display with TGL Platform + Realtek PCON RTD2173 with HDMI2.1 supporting
> panel.

Per IRC chat with Maarten and Daniel, once all the reviews are in, I'll
add a topic branch and apply the patches there, so we can merge the
branch to both drm-misc-next and drm-intel-next.

BR,
Jani.


-- 
Jani Nikula, Intel Open Source Graphics Center