Our custom AM3874 board is based around the DM8148EVM design, and in particular the HDMI output from the device is exactly the same - very simple, with little glue, however we're seeing no signs of life on the diffpairs. The DDC i2c signals work and allow reading of monitor EDID, however we're somewhat at a loss to understand what could be the problem with actual HDMI data output from the AM3874.
The VPSS and HDMI modules load and appear to function exactly as with the EVM. We can write to the framebuffer device with success, configure HDMI resolution, etc, but the output remains dead. We also have an LCD connected to DVO0 which is working perfectly, so the VPSS does appear to be alive and functional, but the HDMI is not.
Would appreciate any advice on understanding what may cause HDMI to fail on an AM3874 / DM8148 design.
