[LinuxPPS] parport-issues

[Cirilo Bernardo]

On Tue, Sep 30, 2008 at 8:12 PM, Bernhard Schiffner
<bernhard at schiffner-limbach.de> wrote:
> Hi,
>
> doing some tests with the parport I found some different behavior in recent
> kernel releases.
>
> If I do an echo "A" > /dev/lp0 with older (2.6.25, Debian Lenny) kernels I see
> no increase in the counting of interrupts.
> Increases only happen if I change the ACK-pin afterwards.
> (see
> http://ml.enneenne.com/pipermail/linuxpps/2008-September/002340.html
> )
>
> Nowadays (26.27-rc3, pps-patches) I do the same and each echo "A" increases
> the interrupt twice but there is no reaction to changes on the ACK-pin.
> (Tested with the same hardware as above.)
>
> Is there any explanation or link?
>
> TIA!
>
> Bernhard
>
> PS:
> Rodolfo patches drivers/char/lp.c but there is the same behavior for
> pps->parallel printer support enabled or not.
>
>

The best thing to do is a diff on the lp modules between 2.6.25 and
2.6.27-rc* to find out why it behaves differently.

- Cirilo