Re: [Bluez-users] Timeout for connections

[Marcel Holtmann <marcel@holtmann.org>]

Hi Mikael,

> I would like to be able to set a timeout for service discoveries (and
> eventually for rfcomm connections as well, but so far I've been
> experimenting with service discoveries). For this I use non blocking
> sockets by passing SDP_NON_BLOCKING to sdp_connect. Then I use select
> with a timeout on the socket, and if it times out I call sdp_close.
> 
> The problem is that after I have done this I can't use the bluetooth
> chip for other connections for some time. Dumping the traffic with
> hcidump, I saw that this is because even though the l2cap socket is
> closed, the bluetooth chip is still doing the connection in the
> background. For this connection to actually get canceled the chip
> needs to be sent a HCI_Create_Connection_Cancel command, but it is not
> sent when the socket is closed.

use a 2.6.19 kernel and this command will be sent.

> To work around this I made some code to send this command myself
> before calling sdp_close. This works, but the problem is that you need
> to be root to send the HCI_Create_Connection_Cancel command. The
> implication being that if you want to set a timeout for service
> discovery, you need to be root. And this can't be the case, am I
> thinking wrong in some fundamental way?

Never ever do that this way. The kernel (and the kernel only) should
control the ACL links.

Regards

Marcel



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