On Wed, 27 Jan 2016, Doug Anderson wrote: > Stefan, > > On Sat, Jan 23, 2016 at 9:08 AM, Stefan Wahren <stefan.wahren@xxxxxxxx> wrote: > > Hi, > > > >> Stefan Wahren <stefan.wahren@xxxxxxxx> hat am 17. Januar 2016 um 04:36 > >> geschrieben: > >> > >> > >> Hi, > >> > >> i have a Cherry G83 USB Keyboard connected to external 4 Port USB hub and this > >> is connected to a Raspberry Pi B (Linux 4.4-rc7). > >> > >> If i disconnect the USB hub from the Pi, i will get multiple of this message: > >> > >> [ 103.558379] dwc2 20980000.usb: --Host Channel 1 Interrupt: Transaction > >> Error-- > >> [ 103.558639] dwc2 20980000.usb: --Host Channel 6 Interrupt: Transaction > >> Error-- > >> [ 103.558709] dwc2 20980000.usb: --Host Channel 7 Interrupt: Transaction > >> Error-- > >> [ 103.558771] dwc2 20980000.usb: --Host Channel 3 Interrupt: Transaction > >> Error-- > >> [ 103.558871] usb 1-1.2: clear tt 1 (9051) error -71 > >> > >> If i reconnect the USB hub everything works as before. > > It would be interesting to find out what the root cause of the > transaction error was, but perhaps things would be a little less bad > with <https://chromium-review.googlesource.com/323773>? You might > need to comment out your "Transaction Error" printouts, but then maybe > things would at least be slightly better? Those errors are actually quite normal. You would get the same sort of thing if you were using a desktop PC instead of a Raspberry Pi (although maybe the messages would be at a lower severity level). The reason is that the computer doesn't know the hub has been disconnected until it sees a status change from the hub's upstream parent, and the status gets polled at intervals of about 250 ms. That leaves plenty of time for attempted transfers to fail. 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
