Re: uart vs sio differences ?

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!

http://www.freebsd.org/cgi/query-pr.cgi?pr=121421

Not sure if the semantics are exactly right, but adding

hint.uart.0.flags="0x100"
hint.uart.1.flags="0x100"
hint.uart.2.flags="0x100"
hint.uart.3.flags="0x100"

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.

         ---Mike