AnsweredAssumed Answered

USB Device and Host port issues on boot

Question asked by Tyler Brandon on Oct 1, 2013
Latest reply on Mar 3, 2014 by Yixing Kong

Linux kernel: 2.6.35

Build system: Timesys Factory

Processor: Freescale i.MX53

Build target: custom board (based on i.MX53 Quick Start Board)


Three USB “ports”: Host1, Host3 and Device.  Host3 and Device ports are exposed externally.

  • A custom Kernel configuration was created to enable the operation of USB Host3 port.
  • A composite CDC USB device (serial + Ethernet + mass-storage) driver is attached to the Device port (note: this driver is compiled into the kernel and is not a kernel module).


Issues description:

  1. When the USB device port is plugged into a PC during boot, the host PC system port sometimes fails to enumerate the Device.  On some PC host systems this happens fairly consistently.  On other systems, this is a rare occurrence (i.e. 1 time in 20 or more attempts).  Re-plugging the cable into USB Device port does not result in the port working.
  2. When certain USB mass-storage devices are plugged into the USB Host3 port on boot, the port will stop working, such that “dmesg” reports nothing when the device is unplugged and re-plugged.


We are looking for solutions or a work-around to these issues.  While rebooting the system without the Host and Device ports plugged in, works around the issue; rebooting is not a viable workaround for us.