Fabien Chevalier wrote:
> Hi Jose,
>
> Please see my comments below.
>
>   
>> Hi Fabien,
>>
>> So your issue is supporting synchronous channels on the UART
>> interface. 
>>     
>
> Well, i would be better if this flow control issue was solved once and 
> for all, for all kind of interfaces :-)
>
> I think it's best to enable synchronous flow control.
>
> Do you know if this feature is supported by bt controllers on the UART 
> interface?
>
> Cheers,
>
> Fabien
>   
Hi Fabien,

It's my understanding from reading the IEEE spec that Bluetooth
compliant devices with UART interface must support synchronous
flow control if they support SCO channels. But I have no experience
with such devices. Has anyone else used such a device?

Attached is a small patch to hci_core.c and hci_usb.c that make the
SCO flow control work. This seems to work well for one SCO. I've
also included a modified hstest.c from bluez-utils/test.

For UART interfaces and possibly for multiple SCO, maybe some
additional changes are required. One issue is that only one queue
is used to communicate with the hci driver. It would be much better
if the synchronous traffic had a separate queue; this guarantees that
the driver can easily access the next SCO packet to transmit.

Jose