[LinuxPPS] parport-issues

[Bernhard Schiffner]

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.