uart vs sio differences ?

Mike Tancsa mike at
Tue Dec 9 14:57:24 UTC 2008

At 05:39 PM 12/8/2008, Mike Tancsa wrote:

>What it appears to be is that as long as data is coming in, even at 
>1200bps, the ioctl FIONREAD returns zero and an actual read does not 
>return any data until there is either a pause in the data coming in 
>or possibly when we do a xmit/write at which point the accumulated 
>data is available for us to read.
>We dont know if this is due to the hardware fifo or something in the 
>driver itself.

OK, I think we found the issue!

Not sure if the semantics are exactly right, but adding


to device.hints fixed the issue!

The next question-- is there a way to do this with the ucom driver as 
well ?  We are seeing the same issue with it.


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