as far as I can see from Android BSPs for iMX8 family, there is no support for DisplayPort for iMX8MQ.
The file signed_dp_imx8m.bin is not even available in the imx-image folder.
Using Android 9.0.0 v2.0.0, I hacked the AndroidUboot.mk and using the file signed_dp_imx8m.bin from Yocto (4.14.98 v2.0.1) I've been able to generate a uboot to enable the DP.
The DisplayPort seems working fine until I unplug and plug again the cable: the link does not come up again, although the driver sense the cable connection.
The unplug/plug sequence works fine using the HDMI.
Has anyone experience with this condition?
May this behavior be somehow related to this commit
According to feedback from Android design team, up to now, the latest android BSP(9.0.0-2.3.1) has not supported the Display Port yet.
Have a nice day!