An interesting addition - If I switch the USB 2 hub for a USB 1.1 Hub, the 
problem goes away.

On Friday, March 7, 2014 6:02:39 PM UTC-8, Terry Hardie wrote:
>
> I'm chasing a problem working on support for Bluetooth 4 LE (Low Energy).
>
> I have 2 vendor's USB bluetooth receivers. 
>
> One is a Cambridge Silicon Radio (0a12:0001) and the other is a 
> Broadcom BCM20702A1 (0a5c:21e8). The Broadcom needs a RAM patch to behave 
> properly, but it outside the scope of this problem. BOTH exhibit the same 
> problem (so I seriously doubt it's a problem with the Bluetooth receivers)
>
> Both devices are operating in HCI mode. I'm running Ubuntu on my 
> BeagleBone Black. I spent a significant time trying to get Bluez 5.15 to 
> build under the standard Angstrom, but never succeeded (too many 
> dependencies I could not satisfy) I started with the standard eMMC flash 
> image, and have worked from there to the point I'm compiling my own kernels 
> for debugging purposes.
>
> I've also built the latest version of Bluez (5.15)
>
> 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've tested these USB receivers under Ubuntu on an Intel machine with the 
> same Bluez 5.15, and the problem is not present.
>
> 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) (pcap for this attached)
>
> 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
>    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
>
> I'm really tearing my hair out over this one. Any suggestions would be 
> greatly appreciated.
>

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