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    SubjectRe: serial flow control appears broken
    Maciej W. Rozycki wrote:

    >On Thu, 26 Jul 2007, Lee Howard wrote:
    >
    >
    >
    >>If the application were to use TIOCM_RTS how would it know when to apply it or
    >>not? Is there some approach that the application could take to manage flow
    >>control on the serial port? What about software flow control? Does the
    >>
    >>
    >
    > Well, an application could negate RTS when it receives a character and
    >is running out of resources for further processing of incoming data.
    >
    > Smarter UARTs may be able to negate RTS themselves based on the amount of
    >data in their receive FIFO. The threshold may be configurable.
    >

    Okay, so let's say we've got a loop around a blocking read on the modem
    file descriptor...

    for (;;) {
    read some data from modem
    process data from modem
    if (end-of-data detected) break;
    }

    Are you suggesting that the application should be using deasserting RTS
    after the read and asserting it before?

    I had previously thought that the control of RTS was something that the
    serial/tty driver was supposed to do independently based on the buffer
    fill. Was I wrong?

    Thanks,

    Lee.
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