Re: sco connection issue for BlueZ 4.x on kernel 2.6.29

[Marcel Holtmann <marcel@holtmann.org>]

Hi,

> >> >> >> Can not accept incoming SCO connection. Kernel version 2.6.29. Kernel
> >> >> >> log is as below. Is this a kernel bug? Is there any fix already for
> >> >> >> this?
> >> >> >>
> >> >> >> <6>[  158.339691] sco_connect_ind: hdev hci0, bdaddr CA:D3:10:55:0C:00
> >> >> >>     -------// receive incoming sco
> >> >> >> <6>[  158.518554] sco_connect_cfm: hcon cf18ee00 bdaddr CA:D3:10:55:0C:00 status
> >> >> >> <6>[  158.721160] sco_connect_cfm: hcon cf149c00 bdaddr CA:D3:10:55:0C:00 status
> >> >> >> <6>[  158.728851] sco_conn_add: hcon cf149c00 conn cc772640
> >> >> >> <6>[  158.734313] sco_conn_ready: conn cc772640
> >> >> >> -----------// handle sco connection complete
> >> >> >> <6>[  158.738800] sco_sock_init: sk cf18c400
> >> >> >> -----------// start handle sco socket
> >> >> >> <6>[  158.742858] __sco_chan_add: conn cc772640
> >> >> >> <6>[  159.693023] sco_sock_accept: sk ccfdf400 timeo 0
> >> >> >> <6>[  159.708038] sco_sock_accept: new socket cf18c400
> >> >> >> <6>[  159.713073] sco_sock_getsockopt: sk cf18c400
> >> >> >> <6>[  159.717834] sco_sock_getsockopt_old: sk cf18c400
> >> >> >> <6>[  159.722839] sco_sock_getsockopt_old: mtu 180
> >> >> >> <6>[  159.727661] sco_sock_getname: sock ce9d80a0, sk cf18c400
> >> >> >> <6>[  159.733398] sco_sock_getname: sock ce9d80a0, sk cf18c400
> >> >> >> <6>[  159.739166] sco_sock_release: sock ce9d80a0, sk cf18c400
> >> >> >> -----------// don't know why it call sco_sock_release
> >> >> >> <6>[  159.745025] sco_sock_clear_timer: sock cf18c400 state 1
> >> >> >> <6>[  159.750671] sco_sock_close: sk cf18c400 state 1 conn cc772640 socket ce9d8
> >> >> >> <6>[  159.758453] sco_chan_del: sk cf18c400, conn cc772640, err 104
> >> >> >> <6>[  159.764770] sco_sock_kill: sk cf18c400 state 9
> >> >> >> <6>[  159.769592] sco_sock_destruct: sk cf18c400
> >> >> >> ------------// destruct sco socket, and disconnect SCO connection
> >> >> >> <6>[  159.782745] l2cap_disconn_ind: hcon cf149c00
> >> >> >> <6>[  159.787384] hci_acl_disconn: cf149c00
> >> >> >> <6>[  159.950805] hci_disconn_complete_evt: hci0 status 0
> >> >> >> <6>[  159.956207] l2cap_disconn_cfm: hcon cf149c00 reason 22
> >> >> >> <6>[  159.961730] sco_disconn_cfm: hcon cf149c00 reason 22
> >> >> >> -------------// sco disconnected
> >> >> >> <6>[  159.967102] sco_conn_del: hcon cf149c00 conn cc772640, err 103
> >> >> >> <6>[  162.130523] hci_disconn_complete_evt: hci0 status 0
> >> >> >> <6>[  162.136291] l2cap_disconn_cfm: hcon cf18ee00 reason 19
> >> >> >> <6>[  162.149871] sco_disconn_cfm: hcon cf18ee00 reason 19
> >> >> >> <4>[  165.382141] done EDISCO CTRL ENABLE
> >> >> >> <7>[  165.386077] sholes-panel:  edisco_ctrl_enable_te
> >> >> >
> >> >> > what kind of program are you using?
> >> >> >
> >> >>
> >> >> This issue was found when testing HFP on android platform with a
> >> >> Bluetooth carkit which is not support eSCO. At first android tries to
> >> >> establish eSCO with carkit, carkit response with error that eSCO is
> >> >> not supported. Then carkit send SCO connect request to android
> >> >> automatically, android accepted this connection but disconnect it
> >> >> immediately.
> >> >
> >> > I think we fixed all of these. Try a 2.6.31-rc5 kernel. Also you would
> >> > need to include the output of hcidump -X -V.
> >>
> >> I think there is a bug in the function sco_sock_getsockopt_old() in sco.c.
> >>
> >> I changed the code like below and then test sco again, incoming sco
> >> connection can be created successfully now.
> >>
> >> @@ -719,7 +715,10 @@ static int sco_sock_getsockopt_old(struct socket *sock, int
> >>                 break;
> >>         }
> >>
> >> -       release_sock(sk);
> >> +    if (err != 0) {
> >> +           release_sock(sk);
> >> +    }
> >>         return err;
> >
> > that is not it for sure. The release_sock() is the unlock function and
> > your patch create a locking imbalance.
>
> This issue is fixed by Johan's commit of "Don't enable the SCO server
> socket when not necessary"
> (http://git.kernel.org/?p=bluetooth/bluez.git;a=commit;h=cd6678404659a1bf6449b5b1d48b17883d895aef)

so if Android would finally start using upstream BlueZ and not ship
their own stuff, we could have avoided this non-sense.

Regards

Marcel