We are setting up the HDMI inputs such that the input colour space is automatically determined (by writing 1111 to INP_COLOR_SPACE). We have OP_656_RANGE set to force a limited range on the output.
If we put in a YUV signal to the HDMI input, it appears that it is incorrectly deciding that this is a limited range input signal, despite table 48 of the hardware guide (page 281 or our PDF) saying that the input range is always 0:255 for YUV. If we manually set this (by setting INP_COLOR_SPACE to 0111), then the output is scaled correctly. (We can see this by feeding in a grey scale image containing 8 grey levels. The top and bottom step sizes are smaller than all the rest, indicating that these are being clipped rather than scaled).
Am I misinterpreting table 48? Or is the 7842 behaving incorrectly in this case?