On Fri, 3 Sep 2004, Toralf Lund wrote: > I'm having some problems with a custom USB device that communicates with > a Linux host running usb-uhci (Red Hat Linux 9, kernel-2.4.20-31.9) > Simply put, bulk read (via libusb usb_bulk_read()) from the device will > sometimes fail. After the system has got into a failure state, all > subsequent also return with error. Device reopen doesn't help, either, > in fact the device sometimes isn't there any longer (i.e. it won't be > returned by a bus scan.) Reloading the kernel module usually puts it > right, however. > > I could give you more details, but I think I'll ask first of all if > anyone can explain what's going on when the following system log > messages occur: > > Sep 3 15:29:58 indonesia kernel: usb-uhci.c: interrupt, status 2, > frame# 915
That doesn't mean anything useful. In fact, that message has been eliminated in later kernel versions. > Sep 3 15:29:58 indonesia kernel: usbdevfs: USBDEVFS_BULK failed dev 2 > ep 0x82 len 108 ret -84 Most of that is pretty clear. Device number, endpoint number + direction, transfer length. The return code -84 is -EILSEQ (you can find it in include/asm-generic/errno.h), and according to Documentation/usb/error-codes.txt, -EILSEQ is a CRC mismatch. In other words, the received packet was invalid -- either it was transmitted wrong or it got garbled. > Sep 3 15:30:01 indonesia kernel: usb_control/bulk_msg: timeout > Sep 3 15:30:01 indonesia kernel: usbdevfs: USBDEVFS_BULK failed dev 2 > ep 0x82 len 32 ret -110 Timeout again is pretty clear. Also -110 is -ETIMEDOUT. The device failed to complete the bulk-in request within the time limit specified by your program. > Sep 3 15:30:04 indonesia kernel: usb_control/bulk_msg: timeout > Sep 3 15:30:04 indonesia kernel: usbdevfs: USBDEVFS_BULK failed dev 2 > ep 0x82 len 32 ret -110 Same as before. > Also, is there anything else I can do to make it easier to track down > the problem? It is probably a device error, but can the driver help me > identify it? Maybe it's not a device problem, maybe it's a bad cable connection. It's impossible to say for sure, since all you know is what the computer received. At this point you probably know almost everything that the driver knows. But you could try looking at the source code for the driver; there might DEBUG options that have been disabled. If you enable them maybe you'll learn more. Alan Stern ------------------------------------------------------- This SF.Net email is sponsored by BEA Weblogic Workshop FREE Java Enterprise J2EE developer tools! Get your free copy of BEA WebLogic Workshop 8.1 today. http://ads.osdn.com/?ad_id=5047&alloc_id=10808&op=click _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
