DisplayPort Dual-MST on Orin

I notice that the Orin TRM (v1.0p) makes reference to both MST and Dual-MST (Display Controller, 1.4.4 “Output”). It notes that Dual-MST is “not supported with YUV 4:2:2 output format”.

Can somebody clarify what exactly Dual-MST is, as the rest of the TRM is a little light on describing it. Does Dual-MST mean “normal” MST with two separate display heads going down the DP interface, or does this Dual-MST mean a special feature of some sort with a single display head which is split into two halves using the Pixel Reorder Unit, then going out as two separate streams?

We would be trying to achieve two separate MST outputs (from two separate heads) at YUV 4:2:2 and are trying to figure out if this is possible.

I think it just indicates MST with separate two displays.

But then what is the purpose of the Pixel Reorder Unit (Display Controller, 2.1.5 “Raster Generator”); the reference to the PRU notes both Dual-MST and Dual-SST, suggesting that the PRU is somehow critical to them.

Could you perhaps ask for a more detailed response internally, as the PRU is not further documented anywhere else in the TRM?


Just checked with internal team. Sorry that my previous comment was wrong.

Dual MST and normal MST are completely different.

Regular DP MST is streaming different streams on multiple displays using multiple heads … In case of Orin, only 2 heads are available … so, only 2 different streams are possible with 2 different heads with different display timings.

Dual MST is generating 2 streams from single head where each stream goes to each half of display monitor(Tiled displays) using pixel reordering … note that here there is single head … so, both streams have same display mode timings.

And currently this Dual MST is not supported. And no plan to support it.

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That’s great. Thanks for clarifying and confirming!

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