Why can I connect the Altera 16550 uart DMA request lines directly to the HPS in QSYS?

Description

The Altera UART 16550 UART IP DMA request lines can\'t be connected up directly to the Altera Arria® 5 and Cyclone® V SoC as it is split in two channels RX and TX.

Resolution

To work around this issue, the DMA channels will have to be exported and connected up externally.
This problem is scheduled to be fixed in a future release of the Quartus II software.