On Tue, 12 Dec 2006, Ethan Romander wrote: > I finally got around to capturing another usbmon trace. For some reason > I wasn't experiencing any keyboard reset events yesterday, but I'm back > to a reset event every couple of minutes today. I'm convinced that the > frequency of reset events has something to do with sun spots. :)
Of more importance is the frequency of errors! > You can find the latest usbmon trace at: > > http://www.papernapkin.org/pastebin/view/3589 > > Note that this trace was captured with the patched usbhid module you > provided to me last Friday. As with the last usbmon trace, this one was > captured with the keyboard as device 6 on the bus. There were no other > devices on the bus, and there was no keyboard activity during the trace. > > An observation: You are correct in guessing that there are fairly > frequent errors occurring on the keyboard's usb bus. The errors appear > similar to: > > ffff810139d06980 79568756 S Ii:006:01 -115 8 < > ffff810139d06980 84594648 C Ii:006:01 -110 0 > > in the usbmon trace. They seem to occur every 5 or 10 seconds, roughly. The most likely cause is a bad USB cable connection. You might want to check the cable, or even check if there's a cable inside the computer case running from the USB port to the motherboard. Try also connecting the keyboard to different USB ports on the computer. > What is interesting is that the device resets are > triggered after a seemingly random number of these errors (e.g. after > nearly 30 errors between the 3rd and 4th resets, but after just two > errors between the 1st and 2nd resets). What matters is not the number of retries but the time interval. It's probably not being handled in the best possible way right now; with that new patch the keyboard will be reset whenever you have two errors (not necessarily consecutive) separated by more than 1 second and less than 3 seconds. Maybe you can suggest a better strategy. However your situation does seem to be unusual; there shouldn't be errors occurring every few seconds. It definitely suggests a hardware problem. > I don't think I remembered to mention before that I have used this > keyboard on a different machine (different linux kernel, completely > different hardware) without any hiccups. Therefore, I expect the > keyboard to be operating properly. I have also operated other devices > on the same bus as the keyboard with my current hardware. The keyboard > gets reset while the other device (a mouse) operated normally. It could be some slight incompatibility between the keyboard and the computer's USB controller. Alan Stern ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Linux-usb-users@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
