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    Subjecthci_ldsic nested locking problem
    Hi,

    when 8250 driver calls uart_write_wakeup(), the tty port lock is already
    taken. hci_ldisc.c's implementation of ->write_wakeup() calls
    tty->ops->write() to actually send the characters, but that call will
    try to acquire the same port lock again.

    Looking at other line disciplines that looks like a bug in hci_ldisc.c.
    Am I correct to assume that ->write_wakeup() is supposed to *just*
    wakeup the bottom half so we handle ->write() in another context ?

    Is it legal to call tty->ops->write() from within ->write_wakeup() ?

    cheers

    --
    balbi
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