Messages in this thread | | | Date | Thu, 20 Nov 2008 14:31:47 +0000 | From | Alan Cox <> | Subject | Re: Question about TTY_DO_WRITE_WAKEUP |
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> Is the TTY_DO_WRITE_WAKEUP bit some kind of cruft that can be removed entirely > or should i generate a patch for serial devices only ?
It shouldn't happen at the serial level. The line discipline sets the flag as and when it has data for the process above.
The expected flow in normal use is
app writes to tty data goes to n_tty ldisc goes to tty n_tty ldisc seems tty blocked n_tty ldisc sets DO_WRITE_WAKEUP
tty gets ucongested calls n_tty write_wakeup SIGIO sent Flag set again
The important part of the logic is in n_tty.c and tty_io.c
Alan
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