But Panel still remains black. So let's address the next road-block :)
Still black - but for the first time I can "detect" if a panel is connected... I.e. some communication is working:
With panel connected:
root@gta04:~# cat /sys/devices/ocp.3/dss.10/0.dsi/display0/backlight/r63311/actual_brightness [ 414.299407] dsi: r63311_get_brightness() [ 414.311004] omapdss DSI error: dsi_vc_read_rx_fifo(ch 1 type DCS) failed [ 414.318481] omapdss DSI error: dsi_vc_dcs_read(ch 1, cmd 0x52) failed [ 414.325592] r63311 display0: read cmd/reg(0) failed: -5 [ 414.331756] dsi: -5=r63311_read(00) [ 414.335784] dsi: read 0
With no panel connected:
root@gta04:~# cat /sys/devices/ocp.3/dss.10/0.dsi/display0/backlight/r63311/actual_brightness [ 263.789581] dsi: r63311_get_brightness() [ 264.292175] omapdss DSI error: Failed to receive BTA [ 264.297393] omapdss DSI error: dsi_vc_dcs_read(ch 1, cmd 0x52) failed [ 264.304229] r63311 display0: read cmd/reg(0) failed: -5 [ 264.309783] dsi: -5=r63311_read(00) [ 264.313476] dsi: read 0
You see the difference?
It is "Failed to receive BTA"
BTA is the MIPI abbreviation for "bus turn around". This means if the panel is connected it responds by sending data back to the OMAP. If it is not connected, that fails of course...
Ok, this is a strong indication that the electrical things (almost) work - but still may be one more roadblock.
And that there is something in the programming sequence for the panel after power-on.
BR, Nikolaus