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RE: [bluetooth-dev] Axis baud rate



What BT HW are you using ?  It looks like you are running the stack in usermode
on a PC, does the serial port support more than 115200 baud ? 

> 
> Hi,
> 
> 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...).

> 
> 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.

> 
> 
> 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

> 
> 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).

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.

> 
> Can U help me ?
> 
> Thks
> 
> franck

/Mattias

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