Question about X-MODE and long distant transmission of SN65DP159

hi,everyone,

In my project, I use SN65DP159 and Xilinx FPGA XC7K410T to design a 4K2K/60Hz monitor with DisplayPort interface. SN65DP159 works in a special mode called X-Mode according to TI's application document <<SLLA358>>, and my hardware design is complied with this document. the monitor can works normally with a DP cable which is less than 2 meters connected to a PC. but if I change to a 5-meters cable, the monitor has no display output. The new cable is tested OK when connect a PC to a samsung 4K2K monitor. So it looks like the SN65DP159 does not work. the attachment is the source code for SN65DP159 including dp159.h, dp159.c, main.h, main.c. I want to know whether the configuration for SN65DP159 is correct or not? How to modify the configuration about SN65DP159 to satisfy long distance signal transmission?

thanks.

上面问题补充：

在阅读代码时，发现配置寄存器地址与datasheet上的寄存器地址不同，《SLLA358》文档中也提到，工作在X-MODE时，许多寄存器在datasheet上是找不到，请问怎样才能从TI获得完整的寄存器描述？

看起来这个问题与cable线的长度有关系，有条件的话可以看一下Input的信号和时钟的眼图。或者直接寄存器调节下接收均衡的值看一下有没有效果。