Hi, I have written a firmware for cypress ezusb fx2 usb controller which
does the basic loop back operation.
Following are my endpoint configuration.

EP2 ---> IN 512 Double Buffered
EP4 ---> OUT 512 Double Buffered
EP6 ---> IN 512 Double Buffered
EP8 ---> OUT 512 Double Buffered

EP4 is connected to EP2 and EP8 is connected to EP6.

Loopback works fine with EP4 and EP2 but fails with EP8 and EP6.
Problem comes once I close the device using usb_close(). Next time when I
open the device using usb_open() and do any transfer it fails with EP8 and
EP6.

I want to know is there any restriction with these EP's. If not then is
there any resetting of registers that has to be done after we close and
open the device.

If required I can post the snippet of my code in the next mail.
Kindly reply.