When ls1046 serdes2 config to pcie x4 ,can serdes1 config to pciex1 ?
This is not possible.
In the QorIQ LS1046A Reference Manual, 31.1.2.1 Rules for SerDes protocol selection it is written:
"• Simultaneous selection of PCIe.1 on SerDes1 and SerDes2 is not allowed."