On Tue, Mar 01, 2011 at 04:41:56PM +0000, Simon Leung wrote: > On 01/03/11 16:37, Greg KH wrote: > > On Tue, Mar 01, 2011 at 04:10:43PM +0000, Simon Leung wrote: > >> Hi all, > >> > >> I'm having a problem with my 3G USB stick (Huawei E220) . > >> > >> The kernel I'm using is version 2.6.21 customized for an ARM board. When > >> I insert the USB stick into the system, normally 3 device show up: > >> /dev/ttyUSB{0,1,2}. The problem I' having is that some time, only the > >> first one shows up and I cannot connect to it. When this happens, > >> normally a reboot will fix it. > >> > >> As I said, this sounds like a kernel/driver issue to me. Could somebody > >> give me some pointers as how to prove/fix it? > > As you are stuck with an obsolete kernel version, please get support > > from the vendor of that kernel, it is very old and we can't do much, if > > anything, about it :( > > > > Can you duplicate this problem on a modern kernel (like one released in > > the past year?) > > > > thanks, > > > > greg k-h > > > > I know. I probably can (and probably will) upgrade the kernel and the > problem will probably go away. But I'd like to take the opportunity and > hopefully learn something. Even knowing which part of the kernel is > handling the usb serial device is fine. The part is in drivers/usb/serial/ and it depends on the actual device you are using, and the host controller you are using. I place the odds on your host controller being the problem, for what it's worth, especially on older ARM kernels like you are stuck with. Best of luck, greg k-h _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies