A1 A2) Modal Operation states where there are one or more Active Modes. Modal Operation ends when there are no longer any Active Modes. It shall be set to one if the product supports Modal Operation. It shall be set to zero otherwise.
A3) "Discover SVID Responder VDO" is not VDM Header. Please read the chapter of "18.104.22.168.2 Discover SVIDs" in the PD Spec.
A4) Discover Mode of Discover Modes Responder ACK contains Mode information.
I am not clear what the question is. Please go through the chapter of "22.214.171.124.3 Discover Modes" in the PD Spec.
Hello Takayama san
Line 36 responds to the Discover Identity command, and there are two SVIDs below.
SVID0: FF01: Discover Modes for Display Port
SVID1: 0x5AC: Discover Modes for Apple SVID
So, I am understanding that the SVID field Shall contain either a 16-bit USB Standard ID value (SID) or the 16-bit assigned to the vendor by the USB-IF (VID). No other value Shall be present in this field.
Q) I want to know the reason why there are two SVIDs mentioned above for Line 36
The client board reports an SVID of 0xFF01, which is an ID assigned to a DisplayPort connection.
0x05AC is VID for Apple and we do not know the detailed apple specific alt mode standard. Ask Apple if required.