Re: [Bluez-users] error on connect

[Marcel Holtmann <marcel@holtmann.org>]

Hi Marco,

> > I don't had the time to search my Broadcom dongles.
>  > Maybe you should try to get yourself some CSR based dongles.
> 
> Unfortunately I'm bound to the broadcom dongles for multipe reasons, so I'd 
> be very grateful if you could take a look at the problem.
> 
> I did some hcidump tests and I think I figured out the source of the 
> problem. Please forgive me that this email contains some information I 
> already postet, it's just to give a whole picture...
> This is the start of a successfull connection (please note my added #N#):
> 
>  > HCI Event: Connect Request (0x04) plen 10
>      bdaddr 00:02:72:C3:F2:10 class 0x3e0100 type ACL
> < HCI Command: Accept Connection Request (0x01|0x0009) plen 7
>      bdaddr 00:02:72:C3:F2:10 role 0x01
>      Role: Slave
>  > HCI Event: Command Status (0x0f) plen 4
>      Accept Connection Request (0x01|0x0009) status 0x00 ncmd 1
> #1#
> #1#
>  > HCI Event: Connect Complete (0x03) plen 11
>      status 0x00 handle 7 bdaddr 00:02:72:C3:F2:10 type ACL encrypt 0x00
> < HCI Command: Write Link Policy Settings (0x02|0x000d) plen 4
>      handle 7 policy 0x0f
>      Link policy: RSWITCH HOLD SNIFF PARK
>  > HCI Event: Command Complete (0x0e) plen 6
>      Write Link Policy Settings (0x02|0x000d) ncmd 1
>      status 0x00 handle 7
> < HCI Command: Change Connection Packet Type (0x01|0x000f) plen 4
>      handle 7 ptype 0xcc18
>      Packet type: DM1 DM3 DM5 DH1 DH3 DH5
> #2# > ACL data: handle 7 flags 0x02 dlen 12
> #2#     L2CAP(s): Connect req: psm 3 scid 0x0040
> 
> 
> If a broadcom dongle is listening, sometimes the ACL packet marked with #2# 
> is received where the #1# lines are. Actually, looking at the hcidump of 
> the sending dongle, that's the time the packet is sent (alway, dongle 
> independant).

do you have a dump where this actually happens?

> It looks like this too early packet now causes the (sensefull) 
> "hci_acldata_packet: hci1 ACL packet for unknown connection handle 6" 
> kernel error message. The dongle then waits for this acl package and thinks 
> this connection is in etablishing phase, so it is blocked.

>>From a quick look at the kernel code, it seems that an ACL packet for an
unknown connection handle may corrupt the HCI flow control.

> The question now is, who is responsible for holding this packed back? The 
> kernel? The dongle itself?

The dongle is responsible for that and actually it is only allowed to
send data packets after the "Connect Complete" event. Otherwise we don't
know its handle and thus can't correctly assign it to a connection.

Regards

Marcel




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