Hi Marcel,

On 05.03.05 12:24:19, Marcel Holtmann wrote:
> > I just got it working by doing a little change in the serial driver 
> > (8250.c). I tested it with 2.6.11 but I think it could work for any 2.6 
> > kernel.
> 
> please provide a patch for your change.

So - after some cleaning - here it is. A short description:

The BlueZ driver requests a baud rate
of 230400 which is uartclk/8 (serial_cs sets uartclk=1843200). However
serial8250_set_termios() refuses to program a baud rate larger than
uartclk/16 which should be ok for most UARTs. I looked into the 2.4
driver and found some code that changes the internal prescaler to values
between 1:16 and 1:4 to support baud rates up to uartclk/4 respectively
(this is done for 16C950 UARTs only). The datasheet of oxford's oxcf950
chip confirms this feature.

Apply the patch to the file drivers/serial/8250.c

Please let me know if there are problems or if it does work.

> > One thing I discovered while debugging this: the hci_uart driver 
> > seems to initialize the actual UART with only 230400 baud. Is this 
> > really the case or are those UARTs clocked at nonstandard (higher) 
> > frequencies so that this setting does result in a higher real baud rate?
> 
> The hci_uart is only a line discipline. Every initialization and baud
> rate settings are done with hciattach.

ok so it's hciattach that sets the baudrate - but that wasn't the point
(or I misunderstood your answer?): I wonder if the bluetooth module is
really accessed at only 230400 baud (that's the rate which is given to
the 8250 driver) which seems a little bit slow thinking of bluetooths
>700kbaud maximum rate...


Regards

Mathias


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