On 2013-01-11, Grant Edwards <grant.b.edwards@xxxxxxxxx> wrote:
> I maintain a serial card driver which, starting with kernel 3.7,
> produces this warning when a port is opened:
>
> tty_init_dev: ttyXYZ driver does not set tty->port. This will crash the kernel later. Fix the driver!
I've been looking at 3.7.2 in-kernel tty drivers to try to figure out
what to do about this, and I don't understand how the in-kernel
drivers are avoiding the same problem I'm seeing.
I've looked at three other tty drivers: amiserial.c, rocket.c,
cyclades.c:
Based on some examination/experimentation, it seems the check for
tty->port is done during driver "installation" and occurs _before_ a
tty driver's open() function is called().
But, amiserial.c doesn't set tty->port until the open() function is
called. How does the amiserial driver avoid the warning and stack
trace?
AFAICT, the rocket.c and cyclades.c drivers don't set tty->port at
all.
What am I missing?
--
Grant Edwards grant.b.edwards Yow! When this load is
at DONE I think I'll wash it
gmail.com AGAIN ...
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