On Fri, 12 Apr 2013, Bruce Guenter wrote: > On Tue, Mar 19, 2013 at 12:12:01PM -0400, Alan Stern wrote: > > If you want to find out what caused those resets, capture a usbmon > > trace for bus 2. It may provide a clue. > > I've finally captured a usbmon trace at a time when it broke, but I'm > not sure what I'm looking at. I'm assuming it's a hardware error at this > point, but my question is what kind of error -- device, cable, > motherboard, etc. > > I've uploaded the (hopefully) relevant bits to > https://gist.github.com/bruceg/5373595 It seems to be a device error. The computer was going along as usual, polling each of the logical units in the card reader to see whether any media had been installed. Then suddenly, the reader started responding with STALLs instead of data. The computer issued a USB port reset, after which the card reader stopped responding altogether. The computer then issued a second port reset, which didn't complete, and a third, which ended in failure. It's safe to say that at this point the reader's high-speed USB interface was kaput. The computer and the reader both switched over to the full-speed (USB-1.1) interface, which seemed to work okay. Now, possibly these device errors were ultimately caused by electrical problems involving the cable, or some sort of interference. If so, there's no way to tell. Does the card reader work better when attached to a different computer? Does a different reader work better on this computer? 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
