Re: [Bluez-users] error on connect

[Marco Trudel <mtrudel@gmx.ch>]

Marcel Holtmann wrote:
> Hi Marco,
> 
> 
>>Do I get this right:
>>- The ACL packet that cause the problem is sent before the connection is 
>>etablished. This is ok and defined in the specification.
> 
> 
> this is not ok and can also not happen since you only get the connection
> handle from the connect complete event. In BlueZ this is indicated with
> the hci_proto_connect_cfm() and only at that time the L2CAP layer starts
> sending out its connect request. Please check the sender side again.

yes. I got this wrong. this way it makes much more sense...


>>- The received dongle is responsible to keep this packet back until the 
>>connection is etablished and process them then.
> 
> In general yes, they should queue the data packet.
> 
> 
>>- the csr dongles seem to handle this correct.
> 
> 
> So far I've never seen this problem with a CSR dongle. Not even with the
> very old ones.
> 
> 
>>- the broadcom dongle seem to don't handle this correct. they probably 
>>suffer a race condition. so they may work or may not work.
> 
> 
> Maybe the stacks Broadcom tested their dongles with are needing some
> time before they can send out the first ACL data packet. Or they do
> other HCI tasks before they start L2CAP. However this is a problem with
> the dongle, because the ACL data packet is not allowed at that time.

ok. that leads me to some questions:
- what would be the behaviour of the listening dongle if you fix the 
flow control after this error occured?
- (just curious) How can you find out that this packet was processed too 
early? does bluez always know the order of processed packets like the 
hcidump shows?
- Are you interested in having this ACL datapacket queue you supposed 
inside bluez (kernel)? respectively, did you mean to do this in the program?

and two comments:
- you told bluez might be too fast for ednet. actually bluez looks like 
it's too fast for the nokia 6230 too. i've to wait 1 second before I 
close a connection, else the mobile phone doesn't get all packets.
maybee this is a bigger problem (the speed thing)...

- I made a try with windows. it played the listening part with the 
broadcom dongle. Unfortunately i haven't a hcidump here, but from more 
than 100 connection tries, every single one worked...
but as I said, this is not reliable because I don't know what windows is 
doing in background...


regards
Marco


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