Hi Marcel, >> >>> I'm having issues where hcidump seems to be losing packets. I'm >> >>> trying to collect traces of avtest running. Avtest properly prints >> >>> out that it sent a packet and received a reply, but I don't always see >> >>> it in hcidump. Seems if I run avtest a lot successively, it does show >> >>> up. I'm running a 2.6.33.20 kernel with hcidump-2.3. Let me know if >> >>> the kernel is just too ancient, but I'd like to know if others have >> >>> seen this type of issue. >> >> >> >> actually hcidump can not loose any packets. Write them into a file in >> >> BTSnoop format and double check with Wireshark or the Frontline Viewer. >> >> >> >> The kernel is always sending the exact copy to the hcidump sockets and >> >> thus there is no way you loose packets. The only explanation would be >> >> that L2CAP socket has a bug and swallows it. Have you checked that >> >> avtest actually reports L2CAP send errors. >> > >> > I was saving in btsnoop and looking at it in wireshark. And verified >> > that the other side got the command by enabling debug mode on >> > bluetoothd. But now I see the packet is sort of there, but it's >> > malformed! >> > >> > Bad: >> > < 02 01 20 07 00 03 00 40 00 00 06 04 >> >> 02 01 20 07 00 03 00 40 00 03 06 31 >> > >> > Good: >> > < 02 01 20 07 00 03 00 42 00 00 06 04 >> >> 02 01 20 07 00 03 00 42 00 03 06 31 >> > >> > Somehow one byte is wrong (40 bad, 42 good). Any ideas on that? Let >> > me know if you'd like the logs, but I verified the --raw output of >> > hcidump had the same issue. >> >> BTW, I would say the issue exists more when SDP is going on (as when I >> run the test a lot before a disconnect, it starts working -- no more >> SDP later on). And we can see that it classified the packet as SDP, >> not AVDTP. I'm tracking the hcidump code now, not entirely sure how >> data goes into one or the other. > > the hcidump code is pure raw data. It is the same data that goes to the > driver. Trust me here, that is how the kernel works, it clones the skb > before sending to the driver and sends a copy back to hcidump. So you > will not find a bug in the hcidump raw data. > > The only way something can go wrong if L2CAP has an issue. Are you using > L2CAP basic modem or enhanced retransmission? Looks like ERTM was added in 2.6.36, and I didn't backport it, so must be basic. -- 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
