Not to sound too negative - I love what you are doing - but using a MIPI DSI -> eDP bridge IC does not get rid of any proprietary blobs.
In practice, those bridge ICs contain general purpose MCU cores, and run a proprietary firmware blob. You can usually update it over I2C. So you've just shifted the blob from one part of the stack (AP firmware) to another (bridge IC firmware).
That is incorrect. There is no updatable firmware blob in the chip that we use: http://www.ti.com/lit/ds/sllseh2b/sllseh2b.pdf?&ts=158895831...
Edit: To explain, the external DP/HDMI TX shares an IP block and even the signal lines. This is also a reason why we’re using a MIPI DSI->eDP converter chip for the internal display, as that path is blob-free.
I wish there was a good blob free USB3 display adapter. Maybe we’ll have to make one.