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    SubjectRe: [PATCH] Add the ability to layer another driver over the serial driver
    > I was actually wrong, flush_to_ldisc does handle reentrancy.
    > It can only have one caller to disc->receive_buf() at a time. So
    > long chains of recursion don't seem to be possible, even if called
    > from IRQ context.

    disc->receive_buf is single threaded but if it then sends characters back
    in the same context (eg flow control) you get re-entry in the driver.

    > And studying the way ppp does writing, it can bypass the tty_write()
    > call and directly call the drivers. So that bypasses the transmit
    > locking problems I saw.

    tty_write() is the layer above the ldisc. tty_write() feeds a line
    discipline from (usually) user space. Line disciplines write direct to
    the tty.

    > This is going to require some more thought. But I believe it can be
    > done with adding a poll routine to the tty_operations structure

    What status do you need to poll ?
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      Last update: 2006-12-11 18:11    [W:0.019 / U:42.216 seconds]
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