On Thu, 5 Jan 2012 j.uzycki@xxxxxxxxxxxxxx wrote: > Hello. > > I have got "almost ready" 2.6.30.10 linux kernel for Atmel's > AT91SAM9G20 CPU. The mainboard has one port connected directly to USB > device and the second port connected to TI's TUSB2046B USB hub. > > The problem is: > CDC-ACM modem (Motorola G24) connected to 9g20 usb port directly works > fine but connected thru tusb2046b hub some data are lost (instead of AT > echo I sometimes get A or T only) and another time I got input/output > error. The test script uses chat, cycled: open ttyACM0 port, send AT and > wait for OK, close the port. > When I compiled the kernel with usb debug option I got (only during > communication thru the hub) at91_ohci cc 5 -> status -62 (ETIME) error. > Now I am going to use usbmon and I started to learn USB low level > protocol. > > I also found the hub's errata > http://www.ti.com/lit/er/sllz051/sllz051.pdf and some codes: > http://www.clearchain.com/blog/posts/resetting-the-usb-bus-under-linux > http://marc.info/?l=linux-usb-users&m=116827193506484&w=2 > However my modem is detected properly. Therefore usb port reset seems > another problem solution. > > Can you give me any advice/clue/tip? For testing purposes, try replacing the hub with a different brand and see if that works better. If it does, you'll know that the TUSB hub is causing the problems. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
