On Sun, Feb 15, 2009 at 09:13:53PM +0530, Shivdas Gujare wrote: > Hi Greg, > Thanks for your help. > > On Tue, Feb 10, 2009 at 2:20 AM, Greg KH <greg@xxxxxxxxx> wrote: > > On Tue, Feb 10, 2009 at 12:26:23AM +0530, Shivdas Gujare wrote: > >> Hi Greg, > >> I am currently testing my device(eZ430) using generic usb-serial > >> driver, and I came across some strange problem. > > > > Ick, generic usb-serial? Why? There's no flow control with that > > driver, and it's extreemly slow. > > > > Also, what kernel version are you using? > > I am using 2.6.29-rc2 from > http://git.kernel.org/?p=linux/kernel/git/tmlind/linux-omap-2.6.git;a=summary That's good. > >> If I test the device with x86, it works very well. It sends character > >> strings to USB serial, after pressing key on device. > >> But when I test with ARM board(Beagle), it shows some characters > >> missed in between.(for ex "Hello" receives as "Helo" with "l" missed) > > > > What host controller driver are you using here? > > It's "Mentor Graphics INVENTRA" musb from drivers/usb/musb/ Ick. Based on the huge number of patches for this host controller driver recently, I'd blame this, and not the usb-serial driver, especially as it seems to work fine for you on an x86 box. > >> What could be the probable reason? How can I debug these problems? > > > > Use a usb protocol "sniffer" to verify that the data really is not > > getting to/from your device to see if there is an overflow in either > > your device, or in the host would be a good place to start. > > > > You can use usbmon for that. > > It seems that device is sending proper data, because it works fine > with x86. I tried to use usbmon > but I can't get any data on "bulk in" endpoints, but I can get every > packet generated on control endpoint > if I disconnect and re-connect device. Why is usbmon not working for you? If you connect to the "send me everything" monitor port, do you not see the data? > Also, I could be wrong, but is it worth to keep null check for > urb->actual_length before calling "usb_serial_debug_data" Which check are you referring to in which file? thanks, 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
