Re: Question on tty line discipline

From: Tilman Schmidt
Date: Sat Mar 03 2007 - 14:59:48 EST


Am 28.02.2007 14:47 schrieb Christopher Meller:
> When the line discipline is set via ioctl from user space to e.g. N_PPP and the userspace program returns without resetting the line discipline back to N_TTY, the serial device cannot be used (ENODV) until an appropriate ioctl (to N_TTY) is performed. Is there any reason for the fact that the line discipline is not reset by the kernel , when closing the device.

Is that really so? While testing a line discipline I have written
myself (N_GIGASET_M101) I came to the opposite conclusion.

Specifically, when I set the line discipline on eg. /dev/ttyS1 to
N_GIGASET_M101 from the user space daemon I have written for that
purpose, and that user space daemon exits, my line discipline is
removed, ie. its .close method is called. That is true even if I
kill the user space daemon by sending it an uncaught signal.

--
Tilman Schmidt E-Mail: tilman@xxxxxxx
Bonn, Germany
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