We have a USB host issue in i.MX 6sx. We connect a FTDI usb device to USB host of i.MX6sx, which is USB2, an EHCI port.
We found if we send the data to the FTDI (it will send back an ACK, then i.MX6sx send the next data), the interval of two data request is too slow. We need the interval about 1ms. There is a latency timer in FTDI, it can be set from 16ms to 1ms. If it's great than 5ms, it's right. But failed small than 5ms, which is about 7-8ms.
And we compared with the program in PC (connected FTDI usb device to USB host of PC), the 1ms interval is OK. Therefore, we don't know whether some setting should be set in iMX6sx. Thank you.