[Bluez-devel] bluetooth dies when trying to use 2 sco links

[Bluez-devel] bluetooth dies when trying to use 2 sco links

[Horacio J. Peña]

[-- Attachment #1: Type: text/plain, Size: 2583 bytes --]

Hello!

Attached you'll find the code for a test program that makes a call using
the hands-free profile connected to a cell phone and when the call is
answered it generates echo (so the person who answers the phone will
hear himself)

Running just one instance of it with just one phone, it works great.
When I try to run two instances, each connected to a different phone, it
works for a few seconds and then all the SCO data stops flowing (hcidump
shows nothing) The bluetooth dongle I'm using has a led indicating it's
working. That led gets off permanently and the phones display an
indication saying something like "bluebooth connection lost"

After that, trying to do an hcitool scan dies with:

Scanning ...
Inquiry failed: Connection timed out

On http://www.compendium.net.ar/2sco.hcidump.bz2 you can find an hcidump
of the tests.

The dongle i'm using is:

Bus 001 Device 004: ID 4851:1103

horape@nb:~$ hciconfig hci0 version
hci0:   Type: USB
        BD Address: 00:0E:A1:00:54:19 ACL MTU: 192:8 SCO MTU: 64:8
        HCI Ver: 1.1 (0x1) HCI Rev: 0x32e LMP Ver: 1.1 (0x1) LMP Subver: 0x32e
        Manufacturer: Cambridge Silicon Radio (10)
horape@nb:~$ hciconfig hci0 revision
hci0:   Type: USB
        BD Address: 00:0E:A1:00:54:19 ACL MTU: 192:8 SCO MTU: 64:8
        Build 814
horape@nb:~$ hciconfig hci0 features
hci0:   Type: USB
        BD Address: 00:0E:A1:00:54:19 ACL MTU: 192:8 SCO MTU: 64:8
        Features: 0xff 0xff 0x0f 0x00 0x00 0x00 0x00 0x00
                <3-slot packets> <5-slot packets> <encryption> <slot offset>
                <timing accuracy> <role switch> <hold mode> <sniff mode>
                <park state> <RSSI> <channel quality> <SCO link> <HV2 packets>
                <HV3 packets> <u-law log> <A-law log> <CVSD> <paging scheme>
                <power control> <transparent SCO>

Kernel is:

Linux nb 2.6.17 #4 SMP PREEMPT Wed May 10 13:53:45 CEST 2006 i686 GNU/Linux

Default with KNOPPIX 5.0.1 2006-06-01

I'm working on a toshiba satellite P105-S6024.

The phones i'm using are sony ericsson z520a. The code assumes rfcomm channel 3 is
hands free profile (line 50) and call indicator 10 is callsetup (line 67)

Is somebody able to help? Is there more info I could provide to help in the search
for a solution?

I'm looking forward to have 7 phones connected to a PC, making calls all
at once almost 24/7. Should I try with 7 dongles, one for each phone?
Would that work better?

Thanks!
					HoraPe
---
Horacio J. Peña
horape@compendium.com.ar
horape@uninet.edu

[-- Attachment #2: handsfree-echo.c --]
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#include <sys/socket.h>
#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>
#include <bluetooth/hci_lib.h>
#include <bluetooth/rfcomm.h>
#include <bluetooth/sco.h>
#include <fcntl.h>
#include <assert.h>

int fd;

void send_line(char* line)
{
  write(fd, line, strlen(line));
  write(fd, "\xd", 1);
  fprintf(stderr, "send_line:<%s>\n", line);
}

const char* get_line()
{
  static char buf[1024];
  char *bufit=buf;
  while (read(fd, bufit, 1)==1 && *bufit!='\xd') {
    if (*bufit=='\xa')
      bufit = buf;
    else
      bufit++;
    }
  *bufit = '\x0';
  fprintf(stderr, "get_line:<%s>\n", buf);
  return buf;
}

int main(int argc, char *argv[])
{
  if (argc!=3) {
    fprintf(stderr, "argc!=3\n");
    return 1;
  }
  
  fd = socket(PF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
  if (fd<0) {
    perror("socket error");
    return 1;
  }
  struct sockaddr_rc addr;
  memset(&addr, 0, sizeof(addr));
  addr.rc_family = AF_BLUETOOTH;
  str2ba(argv[1], &addr.rc_bdaddr);
  addr.rc_channel = 3;
  if (connect(fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
    perror("connect error");
    return 1;
  }
  send_line("AT+BRSF=22");
  while (strncmp(get_line(),"OK",2)!=0);
  send_line("AT+CIND=?");
  while (strncmp(get_line(),"OK",2)!=0);
  send_line("AT+CIND?");
  while (strncmp(get_line(),"OK",2)!=0);
  send_line("AT+CMER=3,0,0,1");
  while (strncmp(get_line(),"OK",2)!=0);

  char dialcmd[1024];
  sprintf(dialcmd, "ATD%s;", argv[2]);
  send_line(dialcmd);
  while (strcmp(get_line(),"+CIEV: 10,3")!=0);
  fprintf(stderr, "alerting! connecting SCO\n");
  
  int scofd = socket(PF_BLUETOOTH, SOCK_SEQPACKET, BTPROTO_SCO);
  if (scofd<0) {
    perror("scofd socket");
    return 1;
  }
  struct sockaddr_sco scoaddr;
  memset(&scoaddr, 0, sizeof(scoaddr));
  scoaddr.sco_family = AF_BLUETOOTH;
  str2ba(argv[1], &scoaddr.sco_bdaddr);
  if (connect(scofd, (struct sockaddr *)&scoaddr, sizeof(scoaddr))<0) {
    perror ("scofd connect");
    return 1;
  }

  char scobuf[100][48];
  int scoit=0;
  while (1) {
    while (read(scofd, scobuf[scoit], 48) == 48) {
      scoit = (scoit+1)%(sizeof(scobuf)/sizeof(scobuf[0]));
      write(scofd, scobuf[scoit], 48);
    }
  }
  return 0;
}

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[-- Attachment #4: Type: text/plain, Size: 164 bytes --]

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Re: [Bluez-devel] bluetooth dies when trying to use 2 sco links

[Brad Midgley]

Horacio

fyi... over a year ago, Marcel wrote this cryptic note on multiple sco
connections:

===========
starting with 2.6.10 the hci_usb got a module parameter "isoc". This
controls the alternate setting when plugging in a dongle. The default
value is 2 (or 0 if it is blacklisted device). Check the Bluetooth
specification what value you have to choose for 2 x 16-bit SCO channels.
===========

If you're not able to find that value, you could try experimenting with
different values.

I was not able to find out what happens if the value is set higher than
you really need it. Would it hurt to load hci_usb with isoc set to the
value for two headsets even if you usually only use one? I don't know.

> Running just one instance of it with just one phone, it works great.
> When I try to run two instances, each connected to a different phone, it
> works for a few seconds and then all the SCO data stops flowing 

Brad

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Re: [Bluez-devel] bluetooth dies when trying to use 2 sco links

[Marcel Holtmann]

Hi Horacio,

> Attached you'll find the code for a test program that makes a call using
> the hands-free profile connected to a cell phone and when the call is
> answered it generates echo (so the person who answers the phone will
> hear himself)
> 
> Running just one instance of it with just one phone, it works great.
> When I try to run two instances, each connected to a different phone, it
> works for a few seconds and then all the SCO data stops flowing (hcidump
> shows nothing) The bluetooth dongle I'm using has a led indicating it's
> working. That led gets off permanently and the phones display an
> indication saying something like "bluebooth connection lost"
> 
> After that, trying to do an hcitool scan dies with:
> 
> Scanning ...
> Inquiry failed: Connection timed out
> 
> On http://www.compendium.net.ar/2sco.hcidump.bz2 you can find an hcidump
> of the tests.
> 
> The dongle i'm using is:
> 
> Bus 001 Device 004: ID 4851:1103
> 
> horape@nb:~$ hciconfig hci0 version
> hci0:   Type: USB
>         BD Address: 00:0E:A1:00:54:19 ACL MTU: 192:8 SCO MTU: 64:8
>         HCI Ver: 1.1 (0x1) HCI Rev: 0x32e LMP Ver: 1.1 (0x1) LMP Subver: 0x32e
>         Manufacturer: Cambridge Silicon Radio (10)
> horape@nb:~$ hciconfig hci0 revision
> hci0:   Type: USB
>         BD Address: 00:0E:A1:00:54:19 ACL MTU: 192:8 SCO MTU: 64:8
>         Build 814
> horape@nb:~$ hciconfig hci0 features
> hci0:   Type: USB
>         BD Address: 00:0E:A1:00:54:19 ACL MTU: 192:8 SCO MTU: 64:8
>         Features: 0xff 0xff 0x0f 0x00 0x00 0x00 0x00 0x00
>                 <3-slot packets> <5-slot packets> <encryption> <slot offset>
>                 <timing accuracy> <role switch> <hold mode> <sniff mode>
>                 <park state> <RSSI> <channel quality> <SCO link> <HV2 packets>
>                 <HV3 packets> <u-law log> <A-law log> <CVSD> <paging scheme>
>                 <power control> <transparent SCO>
> 
> Kernel is:
> 
> Linux nb 2.6.17 #4 SMP PREEMPT Wed May 10 13:53:45 CEST 2006 i686 GNU/Linux
> 
> Default with KNOPPIX 5.0.1 2006-06-01
> 
> I'm working on a toshiba satellite P105-S6024.
> 
> The phones i'm using are sony ericsson z520a. The code assumes rfcomm channel 3 is
> hands free profile (line 50) and call indicator 10 is callsetup (line 67)
> 
> Is somebody able to help? Is there more info I could provide to help in the search
> for a solution?
> 
> I'm looking forward to have 7 phones connected to a PC, making calls all
> at once almost 24/7. Should I try with 7 dongles, one for each phone?
> Would that work better?

it is an idea to go with 7 phones, because the maximum number of SCO
channels per piconet is 3. There is simply no more bandwidth available.
That said, 2 SCO channels should work, but I assume our USB driver or
maybe the old CSR firmware can't really handle that smoothly.

Regards

Marcel



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Re: [Bluez-devel] bluetooth dies when trying to use 2 sco links

[Brad Midgley]

Horacio

> Attached you'll find the code for a test program that makes a call using
> the hands-free profile connected to a cell phone and when the call is
> answered it generates echo (so the person who answers the phone will
> hear himself)

I talked with Marcel about this. Here's the current situation:

uart-connected bluetooth adapters can do multiple sco connections
without any trouble.

usb-connected bluetooth adapters suffer from a limitation in the usb
kernel layer... the number of sco connections has to be hardcoded at
boot time in the isoc parameter. If it's set for two 16-bit sco
connections, when more or fewer connections are in use, no audio gets
through. The usb layer needs a rewrite to fix this.

Brad


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