DSC Support#

DSC can be enabled for a specific serializer and configured in the serializer node within the device tree.

  • Serializer node: contains fields specific to serializer X.

    Each serializer node includes properties related to DSC:

    • supportsDSC set to 1 if DSC is supported by the serializer.

    • supportsFEC set to 1 if FEC is supported by the serializer.

Note

The maxim serializer has a hardware bug when enabling DP FEC with MST (regardless of DSC). If DP FEC is enabled along with MST, it will cause display blank (pixel blank) issue at serializer. The details of it is with ADI. Customer needs to make sure of this issue and enable DP FEC only after consulting ADI with specifically checking if the hardware bug is present in the revision customers using in their platforms.

In the case of MST, all streams are enabled with DSC when the property is set for the respective serializer.

serializer-2 {
    serializer-data-id = <2>;
        maxLinkBW = <0xa>;
        maxLaneCount = <4>;
        supportsMST = <1>;
        supportsDSC = <1>;
        supportsFEC = <1>;
};

display-modes {
        mode-0 {
            timing-id = <0>;
            clock-frequency-khz = <148500>;
            hactive = <1920>;
            vactive = <1080>;
            hfront-porch = <88>;
            hback-porch = <148>;
            hsync-len = <44>;
            vfront-porch = <4>;
            vback-porch = <36>;
            vsync-len = <5>;
            rrx1k = <60000>;
            pps-data = [
            11 00 00 89 30 80 04 38
            07 80 04 38 03 c0 03 c0
            02 00 03 58 00 20 73 3e
            00 0d 00 0f 00 1d 00 0e
            18 00 10 f0 03 0c 20 00
            06 0b 0b 33 0e 1c 2a 38
            46 54 62 69 70 77 79 7b
            7d 7e 01 02 01 00 09 40
            09 be 19 fc 19 fa 19 f8
            1a 38 1a 78 22 b6 2a b6
            2a f6 2a f4 43 34 63 74
            00 00 00 00 00 00 00 00
            00 00 00 00 00 00 00 00
            00 00 00 00 00 00 00 00
            00 00 00 00 00 00 00 00
            00 00 00 00 00 00 00 00 ];
        };
    };

Note

The display-serdes-config property in corresponding serializer opcode dtsi file OR use newly created serializer opcode dtsi file. Only MAX96861 supports DSC and FEC.For Thor reference platform, the file is with this name tegra264-p3960-serdes-max96861-ser-c-gmsl2-dsc-fec.dtsi.

Note

pps-data block is required in mode node for DSC to be enabled.

Limitations#

  • The serializer must support DSC before enabling the feature.

  • The timing node in the device tree should contain the DSC pps-data block corresponding to the serializer or panel.

  • The deserializer must be programmed with the appropriate PPS data for proper decompression.

  • DSC must be supported for FEC to be enabled.

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