On Sun, Mar 14, 2010 at 12:18:16PM +1100, Bernardo wrote: > Greg KH said the following on 03/14/10 02:16: > >On Sat, Mar 13, 2010 at 02:23:17PM +1100, Bernardo wrote: > >>I'm working on an embedded device which our customers can configure (and > >>run some diagnostics) using serial port. The new version of the > >>device has an USB port instead and there is an issue how to let > >>the customers > >>use it to perform configuration in a similar fashion. BTW the > >>customers, for all practical purposes, *always* run Windows on > >>their PCs. > >> > >>After a bit of searching the net an obvious solution was to use the > >>gadget serial module. That worked -- to a degree. When the host was > >>running GNU/Linux everything was fine. However when the host was running > >>Windows (XP) the comms would lock up after a while, usually a > >>few minutes but sometimes in less than a minute. To get the > >>comms working again we needed to disable/enable the USB port on > >>the host side and restart the application on the device, not > >>something that would be acceptable. > > > >Is the lockup happening on the device side, or on the host side? If > >it's on the device, we would have a chance to fix this up. This should > >work properly, as lots of people use it like you are wanting to. I > >would recommend working through this to try to solve the issues as it > >seems you are almost there. > > > >greg k-h > > > > Hi Greg, > > My impression was that the host side was seizing up. Don't remember > seeing anything unusual in /var/log/messages on the device but will > double check it when back at work. > Also, g_serial never had to be unloaded/loaded again to get things > back to normal, when i tried doing that - it made no difference. But > on the host side i did have to disable/re-enable the USB port to get > the comms going again. Given that with a Linux host everything was > working just fine it seemed like the Windows driver was flaky. This wouldn't be the first time that people have reported that windows driver as having issues. I suggest filing a bug with Microsoft about it. > Initially I didn't want to unnecessarily confuse the issue but there > is a bit more to the story and it may be worth mentioning; our > application (on the device side) is a multi threaded one where a > separate thread is reading/writing to the port; when it was replaced > with a bare bone test program that just reads from USB port and > echoes lines back (literally less than 10 lines of code) I didn't > see any lockups. This was puzzling but I'd really need to write a > test program on the host side, pumping more input to confirm there > is indeed no lockup. I was just using Hyperterminal (and TeraTerm > too, made no difference) for quick testing. I don't know much, if anything, we can do about this on the Linux side, sorry. It looks like you need to contact Microsoft and work with them on resolving this issue. good luck, greg k-h -- 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
