I have a imx6q customized board which connect the usb device as follow:
CPU USB HOST1 -> USB HUB(AU6259) -> USB to Serial (XR21V1410 or FT232BL)
I use the attached program to do the stress test on both usb serial ports. However, The usb driver will hang after some minutes or hours.
The system still work while the usb driver hang, but I couldn't use any usb devices via the usb hub. I have to reboot the system to let them work again.
There are some methods to accelerate the duplication:
1. Add u-boot parameter "maxcpus=0" or build non-smp kernel.
2. Add other bus loading such as i2c, spi and gpu loading.
3. Add cpu loading.
I have tested the following kernel and all of them have same issue:
1. 3.0.35 kernel on 4.0.0 BSP
2. 3,0,35 kernel on 4.1.0 BSP
3. 3.10.17_ga kernel on Freescale git server
Original Attachment has been moved to: usbserialtest.c.zip