imx6ull Uart5 Rx/Tx problem in L4.14.98

[guochgz]

Hello

      I have change the baseline from L4.1.15 to L4.14.98. then faced a new problem. that the uart(5) rx/tx is not stable. pls see:

      

      I keep typing in char '2', but the seems the some bytes is wrong. 

      I have read this topic:

      imx6ul - UART Rx dropping/corrupting bytes 

      so there is two question:

      1:  How to change the default configuration of UART, DMA or interrupt.

      2:  How to increase rx/tx recieve buf size? 

[igorpadykov · Accepted solution]

Hi 国承 张 

as mentioned on above link: " Using flow control (RTS/CTS) for UART with

DMA is absolutely necessary to avoid data lost."

For changing to interrupt configuration one can try to remove "dma" in dts, as in "uart1":

imx6ul.dtsi\dts\boot\arm\arch - linux-imx - i.MX Linux kernel 

Seems "buffer size" implies threshold levels  in UARTx_UFCR register.

Best regards
igor
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