Hi experts, I have one question about 'read' system call of sco socket. I'm using an open source library which implements bluetooth handfree profile on linux platform. About our use case, cell phone works as audio gateway that all audio received on cell phone will be streamed to linux PC, and vice versa. Everything works just fine of audio streaming above bluetooth channel. But our special application is very sensitive on timing that we need send/receive bluetooth audio frame every 20ms. Regarding sending direction, I can tweak MTU of bluetooth donglel installed on my linux PC. Let's say, MTU is set to 320 bytes, so every 20ms 'send' system call only needs be called one time. ( the audio frame conveyed aboved bluetooth is of signed linear 16bit per sample, 8K sampling-rate ) But this does not affect receiving direction that every 'read' system call on sco socket returns exact 48 bytes. Also I find such 'read' event on linux 'poll' is triggered every 10ms. Every 10ms, such 'read' action is invoked, but it takes 3 or 4 times invokation ( sometimes 3 , sometimes 4) of 'read' to consume this 'read' event, which results in 'EAGAIN'. So every 20ms, I get 288 (48*6) or 336 (48*7) bytes, not exact 320 I expect. Shortly, my question is how to receive ( 'read' system call ) exact 320 bytes every 20ms. Thanks Kandy -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
