$ sudo cat /sys/kernel/debug/dri/0/i915_dp_mst_info
mst: ffff88041796b840, 0
port: 3: ddps: 0 ldps: 0, ffff880412670000, conn: ffff880412670400
port: 2: ddps: 1 ldps: 1, ffff8804128b3400, conn: ffff8804128b2800
port: 1: ddps: 1 ldps: 1, ffff8804128b7c00, conn: ffff8804128b6400
port: 0: ddps: 1 ldps: 0, ffff8804128b7800, conn: (null)
vcpi: 7
vcpi 0: 1 1 10
vcpi 1: 2 2 13
vcpi 2:unsed
payload 0: 2, 1, 10
payload 1: 2, 11, 13
payload 2: 1, 24, 0
dpcd: 12 14 c4 01 00 15 01 83 02 00 00 00 00 00 04
faux/mst: 00 01
mst ctrl: 07
payload table: 03 01 01 01 01 01 01 01 01 01 01 02 02 02 02 02 02 02 02 02 02 02 02 02 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
