Struggling with 128 as a quasi-magic number. I guess anyone wanting to verify this needs to educate themselves on EDID on Wikipedia, as I just did, and learn that an EDID is at least 128 bytes long. Which also explains the hardcoded 128-byte array from ddcutil, which this code relies on.
I wonder if this can be presented in a more approachable manner. Not sure how exactly though, as sizeof(displayInfo->edid_bytes) relies on the fact that ddcutil defines it as byte array rather than byte pointer, and constexpr size_t EDID_MIN_SIZE = 128; implies that the size could be larger but the ddcutil byte array is always constant.
Perhaps an explanatory comment will do the best job?
Like,
// An EDID is at least 128 bytes long, ddcutil exposes the first 128 bytes.