Hi Terry, On Sat, Mar 8, 2014 at 3:19 AM, Terry Hardie <terryh@xxxxxxxxx> wrote: > The problem is when running a lescan (hcitool lescan) with a LE device in > paring mode, which is transmitting a lot of LE Advertising report packets, > the HCI drivers eventually loses sync. I've traced it down to a duplicate > USB fragment. I think your logs show missing USB packets (not duplicated)... More details below. > I added some code to btusb_intr_complete to print each urb as it comes up > from the USB stack. Here's the output for the above problem. Note the extra > "00 02 c7" -- Should not be there... > > Mar 8 06:32:12 arm kernel: [ 122.915094] hci1 urb df4a8540 status 0 count > 16 flags 768 > Mar 8 06:32:12 arm kernel: [ 122.915176] hci1 urb contents: 3e 21 02 01 > 00 01 3c 30 05 7c f9 e1 15 02 01 05 > Mar 8 06:32:12 arm kernel: [ 122.916004] hci1 urb df4a8540 status 0 count > 16 flags 768 > Mar 8 06:32:12 arm kernel: [ 122.916085] hci1 urb contents: 0d 09 53 63 > 6f 73 63 68 65 20 50 52 4f 58 03 19 > Mar 8 06:32:12 arm kernel: [ 122.916985] hci1 urb df4a8540 status 0 count > 3 flags 768 > Mar 8 06:32:12 arm kernel: [ 122.917018] hci1 urb contents: 00 02 c2 > Mar 8 06:32:12 arm kernel: [ 122.942995] hci1 urb df4a8540 status 0 count > 3 flags 768 There is a missing whole 16 byte USB packet right here. > Mar 8 06:32:12 arm kernel: [ 122.943028] hci1 urb contents: 00 02 c7 The bytes above are part of the Advertising data, plus the RSSI (the last byte) for the truncated packet. > I used usbmon to do a "sniff" of the USB traffic. Here's a snippet of a > correct HCI LE Advertising report event, followed by one where the middle > fragment is repeated (frame 1300 is a repeat) This is a different capture > from the above example. I can provide the pcap somewhere if needed > > No. Time Source Destination > Protocol Length Info > 1291 2014-03-07 02:40:16.942573 host 3.1 > USB 64 URB_INTERRUPT in > 1292 2014-03-07 02:40:16.959480 3.1 host > HCI_USB 80 Rcvd Fragment > 3e21020100013c30057cf9e115020105 > 1293 2014-03-07 02:40:16.959624 host 3.1 > USB 64 URB_INTERRUPT in > 1294 2014-03-07 02:40:16.960449 3.1 host > HCI_USB 80 Rcvd Fragment > 0d0953636f736368652050524f580319 > 1295 2014-03-07 02:40:16.960546 host 3.1 > USB 64 URB_INTERRUPT in > 1296 2014-03-07 02:40:16.961455 3.1 host > HCI_EVT 67 Rcvd LE Meta (LE Advertising Report) > 0002ae > 1297 2014-03-07 02:40:16.961560 host 3.1 > USB 64 URB_INTERRUPT in > 1298 2014-03-07 02:40:16.981627 3.1 host > HCI_USB 80 Rcvd Fragment > 3e21020100013c30057cf9e115020105 > 1299 2014-03-07 02:40:16.981696 host 3.1 > USB 64 URB_INTERRUPT in > 1300 2014-03-07 02:40:17.002651 3.1 host > HCI_USB 80 Rcvd Fragment > 3e21020100013c30057cf9e115020105 There are two missing fragments between right here. > 1301 2014-03-07 02:40:17.002720 host 3.1 > USB 64 URB_INTERRUPT in > 1302 2014-03-07 02:40:17.003560 3.1 host > HCI_USB 80 Rcvd Fragment > 0d0953636f736368652050524f580319 > 1303 2014-03-07 02:40:17.003649 host 3.1 > USB 64 URB_INTERRUPT in > 1304 2014-03-07 02:40:17.004567 3.1 host > HCI_USB 67 Rcvd Fragment > 0002b5 In summary, it is expected that for devices that don't change address, the only byte to change is the RSSI (last byte of the last fragment). That's why the 2 first fragments are usually the same for all advertising packets. -- Anderson Lizardo http://www.indt.org/?lang=en INdT - Manaus - Brazil -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
