[Bluez-users] Use an ACL link when an SCO link is established

[Michel Leconte <leconte.michel@cegetel.net>]

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Hi all,

my goal is to use an ACL link when an SCO link is established.

I work with two bluetooth development kits from Semtech-Xemics (SE1441). 

They are compliant Bluetooth v1.2. For the following explanations, one kit is noted "A" and the other "B".

1) First, I create an ACL link between "A" and "B" with : hcitool cc BD_ADDR of "B",

2) Once the ACL link is done, "A" execute an "HCI_Setup_Synchronous_Connection" command to "B",

3) At the event of an SCO request connection, "B" respond with an "HCI_Accept_Synchronous_Connection_Request" command.

4) When the SCO link is established, a "Synchronous Connection Complete" HCI event is visible from the hci layer of each kit.

the "hcitool con" gives :

> SCO AA:AA:AA:AA:AA:04 handle 0 state 5 lm SLAVE

> ACL AA:AA:AA:AA:AA:04 handle 0 state 1 lm SLAVE



5) I try to use the ACL link with a l2ping command from B to A

the l2ping command gives :

l2ping AA:AA:AA:AA:AA:04 (BD_ADDR of A)

Ping: AA:AA:AA:AA:AA:04 from AA:AA:AA:AA:AA:05 (data size 44) ...

no response from AA:AA:AA:AA:AA:04: id 0

no response from AA:AA:AA:AA:AA:04: id 1

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Question 1 : With this configuration (SCO and ACL links between A and B), why l2ping doesn't work ? 

The ACL link can be used isn't it ?



Question 2 : From the hci dump of each side, I notice that there is a difference between the information

of the command and the OGF and OCF between the parenthesises. See below the hcidump results, the 

 red lines are those which give me a problem. At the "A" side, I send an "HCI_Setup_Asynchronous_Connection" and hcidump indicates an  "HCI_Accept_Synchronous_Connection". I get a similar problem in "B" side an "HCI_Reject_Synchronous_Connection " instead of an " HCI_Accept_Synchronous_Connection ".

When you see the bluetooth spec :

HCI_Setup_Asynchronous_Connection is OGF=0x01 and OCF=0x28 

HCI_Accept_Synchronous_Connection is OGF=0x01 and OCF=0x29 

HCI_Reject_Synchronous_Connection is OGF=0x01 and OCF=0x2A 

 

Do these differences are benign for the bluez stack or they can be the origine

of my problem ??




************************** HCI dump from "A" ***********************************************

HCI sniffer - Bluetooth packet analyzer ver 1.30

device: hci0 snap_len: 1028 filter: 0xffffffff

< HCI Command: Create Connection (0x01|0x0005) plen 13

bdaddr AA:AA:AA:AA:AA:05 ptype 0xcc18 rswitch 0x01 clkoffset 0x0000

Packet type: DM1 DM3 DM5 DH1 DH3 DH5 

> HCI Event: Command Status (0x0f) plen 4

Create Connection (0x01|0x0005) status 0x00 ncmd 1

> HCI Event: Connect Complete (0x03) plen 11

status 0x00 handle 0 bdaddr AA:AA:AA:AA:AA:05 type ACL encrypt 0x00

< HCI Command: Write Link Policy Settings (0x02|0x000d) plen 4

handle 0 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 0

< HCI Command: Accept Synchronous Connection (0x01|0x0028) plen 17

handle 0

40 1F 00 00 40 1F 00 00 FF FF C1 01 00 04 00 

> HCI Event: Max Slots Change (0x1b) plen 3

handle 0 slots 5

> HCI Event: Command Status (0x0f) plen 4

Accept Synchronous Connection (0x01|0x0028) status 0x00 ncmd 1

> HCI Event: Synchronous Connect Complete (0x2c) plen 17

status 0x00 handle 256 bdaddr AA:AA:AA:AA:AA:05 type SCO

Air mode: u-law log

************************** HCI dump from "B" ***********************************************


HCI sniffer - Bluetooth packet analyzer ver 1.30

device: hci0 snap_len: 1028 filter: 0xffffffff

> HCI Event: Connect Request (0x04) plen 10

bdaddr AA:AA:AA:AA:AA:04 class 0x3e0100 type ACL

< HCI Command: Accept Connection Request (0x01|0x0009) plen 7

bdaddr AA:AA:AA:AA:AA:04 role 0x01

Role: Slave

> HCI Event: Command Status (0x0f) plen 4

Accept Connection Request (0x01|0x0009) status 0x00 ncmd 1

> HCI Event: Connect Complete (0x03) plen 11

status 0x00 handle 0 bdaddr AA:AA:AA:AA:AA:04 type ACL encrypt 0x00

< HCI Command: Write Link Policy Settings (0x02|0x000d) plen 4

handle 0 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 0

< HCI Command: Change Connection Packet Type (0x01|0x000f) plen 4

handle 0 ptype 0xcc18

Packet type: DM1 DM3 DM5 DH1 DH3 DH5 

> HCI Event: Command Status (0x0f) plen 4

Change Connection Packet Type (0x01|0x000f) status 0x00 ncmd 1

> HCI Event: Connection Packet Type Changed (0x1d) plen 5

status 0x00 handle 0 ptype 0x0018

Packet type: DM1 DH1 

> HCI Event: Connect Request (0x04) plen 10

bdaddr AA:AA:AA:AA:AA:04 class 0x3e0100 type SCO

< HCI Command: Accept Connection Request (0x01|0x0009) plen 7

bdaddr AA:AA:AA:AA:AA:04 role 0x01

Role: Slave

> HCI Event: Command Status (0x0f) plen 4

Accept Connection Request (0x01|0x0009) status 0x00 ncmd 1

< HCI Command: Reject Synchronous Connection (0x01|0x0029) plen 21

bdaddr AA:AA:AA:AA:AA:04

FF FF FF FF FF FF FF FF FF FF C1 01 FF 04 00 

> HCI Event: Command Status (0x0f) plen 4

Reject Synchronous Connection (0x01|0x0029) status 0x00 ncmd 1

> HCI Event: Synchronous Connect Complete (0x2c) plen 17

status 0x00 handle 256 bdaddr AA:AA:AA:AA:AA:04 type SCO

Air mode: u-law log



Question 3 : The event "Synchronous Connect Complete" gives the handle of the SCO link

in my case the handle value is 256. But when you see upside the hcitool

con result gives a handle 0 ? Is it normal ? 


Question 4 : Here's my software configurations : hcidump 1.30 bluez-libs-2.25 bluez-utils-2.25 linux-debian 2.6.12.2 with an ARM target 



As I have to keep the kernel 2.6.12.2, with wich higher version of bluez-libs, bluez-utils and hcidump can I use to be compliant with my kernel ? 



Thanks to all for any suggestions..

warm regards

Michel

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the result of an "hciconfig -a" is :

hci0: Type: UART

BD Address: AA:AA:AA:AA:AA:04 ACL MTU: 339:8 SCO MTU: 180:8

UP RUNNING PSCAN ISCAN

RX bytes:522 acl:0 sco:0 events:61 errors:0

TX bytes:1367 acl:15 sco:0 commands:26 errors:0

Features: 0xff 0xff 0xbd 0xf8 0x1b 0x18 0x00 0x80

Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3

Link policy: RSWITCH HOLD SNIFF PARK

Link mode: SLAVE ACCEPT

Name: 'BlueZ (0)'

Class: 0x3e0100

Service Classes: Networking, Rendering, Capturing

Device Class: Computer, Uncategorized

HCI Ver: 1.2 (0x2) HCI Rev: 0x0 LMP Ver: 1.2 (0x2) LMP Subver: 0xc

Manufacturer: Newlogic (23)

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