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RE: [bluetooth-dev] Bad baud rate error.



Hi, 

we have had problems with this aswell when running on slow machines. Depending on what priority you serial port has (IRQ) there might be  distortions on the received serial data which causes sync errors in HCI. 
You might try to change the IRQ setting for the serial port.

Normally, this message occurs when there has been some error in setting the baudrate of the HW (during initialization only) and the HW responds on a baudrate which is not set in the host. Therefore we added a small note too check this, however this is not the case here. 

However, it can happen once in a while also on a faster machine even if it is more uncommon. For example if you are running the stack in usermode on a reasonably fast machine (PII 266 Mhz) and start a new xterm while sending lots of data over the link there are sync errors. You think that this shouldn't happen... but on the other hand there are usually not any problems with this when running standard ppp traffic over the serial port.
If something gets trashed it is only for the ip-layer to resend the data. 
In bluetooth, HCI relies on a error free data stream....

I don't know if this is a problem when using USB ? Has anyone experienced this on USB ?

If anyone has a solution for this problem please share you ideas and we'll try to fix it. 

There are a define in hci.c which adds a timer which checks if a packet hasn't been successfully assembled for x sec we assume that there is a lost sync and try to reset the HCI state machine.  You might try that but it is not a very good solution (#define HCI_RCV_TIMER 1).

brgds
Mattias

> -----Original Message-----
> From: Seyed Majid Emami [mailto:memami@xxxxxxx.edu]
> Sent: Saturday, September 23, 2000 12:38 AM
> To: mattias@xxxxxxx.com
> Cc: bluetooth-dev@xxxxxxx.com
> Subject: [bluetooth-dev] Bad baud rate error.
> 
> 
> 
> Hello,
> 
> I am running the bluetooth stack on two 486's. When I ftp 
> from one to the
> other and I try to transfer small files things are happy.  
> When I try to
> transfer anything in 100's of kilobytes after a few seconds I 
> receive the
> error message: "Bad UART baud rate ? Check if baudrate really was
> successfully set in HW".  
> 
> I expect this to be a buffer overflow problem since ftp works 
> for small
> sized files.  Could it really be the baud rate though?  And 
> if it is an
> over flow problem because the computer is slow (486) how 
> could I fix it?
> 
> Thanks,
> 
> Majid.
>