imx6ul uart read data reponse slow

[jinghangliu]

Hi, 

     I'm  useing  imx6ul runing the kernel  linux3.14.38, when I read data from the /dev/ttymxc3 the other side connect with a MCU.  When imx6ul send a data to  the MCU it will return data within 5ms .  But I have a test , If send data less than 171ms, the ttymxc3 can't read data.  So I can't read return data from MCU. In imx6ul, I use select to read data.  Where i can modify that let me read data whin 5ms?

[igorpadykov]

Hi  jinghang

please try to build minimal configuration as describes

Table 1. Freescale Yocto project images, core-image-minimal

attached Yocto Guide.

Best regards
igor
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[jinghangliu]

I was already buided a zImage.  with the same app program, PC linux could repsonse very fast, about within 1ms also could read data. But cross compile to imx6ul it need at least 170ms could read data.  I use mark and space parity.