Visible to Intel only — GUID: vgo1418042544365
Ixiasoft
Visible to Intel only — GUID: vgo1418042544365
Ixiasoft
11.8. Sink MST Registers
MST controller control.
Address: 0x00a0
Direction: RW
Reset: 0x00000000
Bit |
Bit Name |
Function |
---|---|---|
31 | VCPTAB_UPD_FORCE | This flag always reads back at 0. 1 = Force VC payload ID table update. |
30 | VCPTAB_UPD_REQ |
|
29:20 | Unused | |
19:16 | VCP_ID3 | VC payload ID for Stream 3
Note: Legal value 0-4
|
15:12 | VCP_ID2 | VC payload ID for Stream 2
Note: Legal value 0-4
|
11:8 | VCP_ID1 | VC payload ID for Stream 1
Note: Legal value 0-4
|
7:4 | VCP_ID0 | VC payload ID for Stream 0
Note: Legal value 0-4
|
3:1 | Unused | |
0 | MST_EN | 8B/10B Channel Coding: Enable or disable MST
128B/132B Channel Coding: Reserved |
When you assert VCPTAB_UPD_FORCE, the sink forces the VC payload table contained in DPRX_MST_VCPTAB0 through DPRX_MST_VCPTAB7 to be taken immediately into use.
When you assert VCPTAB_UPD_REQ, the sink requests the VC payload table contained in DPRX_MST_VCPTAB0 to DPRX_MST_VCPTAB7 to be taken into use after the next ACT sequence is detected.
The VC Payload ID values (1–15) used for VCP_ID0 to VCP_ID3 are different from those used by the DisplayPort source (1–63). The GPU must remap these values. The values used have to match those in the VC Payload ID table—DPRX_MST_VCPTAB0 to DPRX_MST_VCPTAB7 registers.
MST controller status
Address: 0x00a1
Direction: RO
Reset: 0x00000000
Bit |
Bit Name |
Function |
---|---|---|
31 | Unused | |
30 | VCPTAB_ACT_ACK |
|
29:0 | Unused |
VCPTAB_ACT_ACK resets to 0 when VCPTAB_UPD_REQ deasserted. VCPTAB_ACT_ACK is set to 1 if VCPTAB_UPD_REQ is asserted and the ACT sequence is detected, signaling that the table contained in DPRX_MST_VCPTAB0 to DPRX_MST_VCPTAB7 registers have been taken into use.