TUSB551: We use TUSB7340+TUSB551RWBR in server project. When performing read/write test, we found device down

we did a lot of test and  found some patterns：

1.when use TUSB7340+TUSB551RWBR to connect different types of equipment(USB flash disk/USB3.0 to SATA cable):

eye-pattern in mask, no device down;

eye-pattern appears outside the mask(eye-pattern fail), found device down in the probabilistic

2.when use TUSB7340 without TUSB551RWBR to connect USB cable:

If physical layer handshake successfully, even eye-pattern fail, no device down;