On Wed, 30 May 2012, MC Potgieter wrote: > On Wed, May 30, 2012 at 8:23 AM, MC Potgieter <bluscape@xxxxxxxxx> wrote: > > On Tue, May 29, 2012 at 10:24 PM, MC Potgieter <bluscape@xxxxxxxxx> wrote: > >> I'm running linux kernel 2.6.38 on an embedded platform (Mini2440). On > >> the platform I have a Silabs CP2102 USB to serial bridge IC and a USB > >> host interface. I enumerate the USB host interface as a serial gadget. > >> > >> 1.) I have a problem reading data from the CP2102 UART on the platform > >> but I can always write to it. The read will work for a few seconds and > >> then stop working. > >> > >> 2.) On the serial gadget I can always read but write will work for a > >> short while and the stop working. > >> > >> I connect my platform to a test PC via a serial cable, coming from the > >> CP2102 on the platform, and a USB cable, coming from the host > >> interface on the platform. > >> > >> The serial gadget enumerates on the test PC as a com port and I can > >> communicate over it for a while. But if the interface is idle for a > >> while I can only write to it with no response from the platform. > >> > >> For the CP2102 I can always receive data on the test PC but writing to > >> the platform has no effect. > >> > >> What could this be and how can I resolve it. > > > > So it seems like the one direction on both interfaces stops working > > after being idle for a while. > > I'm not a linux expert. Is there some way I can debug these interfaces > to try and determine what is going on? I don't know how you debug problems with a serial connection. For the USB connection, you can use usbmon on the host (see Documentation/usb/usbmon.txt). On the gadget side you can enable CONFIG_USB_GADGET_DEBUG and see what shows up in the dmesg log. 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
