[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [bluetooth-dev] Axis baud rate



>What BT HW are you using ?  It looks like you are running the stack in 
>usermode

It is Ericsson RDK 10100821 PE3

>on a PC, does the serial port support more than 115200 baud ?
Yes, it does

> > I use release 20010108 AXIS BT on a x86 under kernel 2.4. I
> > need to send data with a minimum baud rate of 24 kb/s but this > cadence 
>seems not to be supported by AXIS stack.
> >
> > If we follow the bluetooth specification :
> >
> > First, bluetooth is expected to support up to 128 kb/s,  it
> > is not true with Axis stack.
>
>It is expected to support 723 kbps, however you need a serial port >which 
>supports it aswell (or USB...).
I use a serial port who supports it

> > Second, bluetooth should be able to send  packet with a len
> > up to 4096, it is not true with Axis stack.
>
>on what layer ? this is configurable for each layer.
I configured MTU of each layer from RFCOMM to HCI

> > So when I try to send packet with a baud rate of 12 kb/s, there is
> > congestion during send process and receive process. I try to
> > change value of
> > RFCOMM, L2CAP and HCI MTU but the max value available is 800.
>
>also configurable... see hci.h #define HCI_IN_SIZE 800
I configured it but it seems that send process see always 800 
(send_acl_packet hci. line 2840)

> > For the send process, I identified one problem : one thread
> > is created for each send.
>
>
>where ? if you are talking about the usermode stack this creates
>one thread used to read data from serial port and feed hci,
>and one to write data to the pty (bt_receive_top).
Yes I always work on usermode. It seems that there is one thread for each 
send...

>On the same connection, a unique structure is used
> > to send data
> > (bt_tx_buf in btcommon.h --> line 172), the problem is that
> > this structure
> > is not thread-safe : at high baud rate, at the same time, 2
> > or more threads
> > worked on this structure, so concurency problems occured and
> > send process
> > failed.
>
>some logs could be very useful.
During debug of send process, I added two printf (trace1, trace2) in 
send_acl_packet function (hci.c) :
- At low baud, I can see : "trace1 ... trace 2 ... trace 1 ... trace 2"
- At high baud, I can see : "trace 1... trace 1 ... trace 2 ... trace 2"
This why, I think there is one thread by send

franck
_________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.

-
To unsubscribe from this list: send the line "unsubscribe bluetooth-dev" in
the body of a message to majordomo@xxxxxxx.com