> PPP's write_wakeup then does some complicated stuff which isn't quite
> irq safe, but could probably be made so.
(2.3.x ppp is probably not SMP safe anyway - it has bugs in it that are
fixed in 2.2.15pre but not yet 2.3.x)
> Are you saying that the line discipline's write_wakeup should be a
> simple function to queue the line discipline's BH (that's what "wakeup"
> means to me), or that write_wakeup must be called from BH context by the
> serial driver?
Take a look at the transmit interrupt handling in the serial.c code. The
irq code polls the THRE bit and if it indicates room it stuffs bytes down
the pipe
If the internal buffer is empty it wakes up a task queue on tq_serial. The
bh context code calls the ldisc wakeup
Alan
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