Re: Serial driver changes from v5 to v7

Per Hedeland <per@xxxxxxxxxxxx> wrote:
Hm, so you've added that stuff to the printcap entry based on a
comparison w stty output on 5.x? Because it wasn't in the entry that you
posted at the start of this thread...

That's correct: I attempted to duplicate in the 6.2 printcap the stty
flags observed on the 5.5 host which printed successfully

From what I can tell, the -brkint flag and the -icanon flags are not
set in agreement with the ms= values in /etc/printcap.


The setting of brkint isn't likely to matter, but icanon could quite
possibly do so - basically -icanon allows for character-by-character
input, while icanon will collect a full line before anything is made
available to the program.

It looks as if -icanon was the key to the puzzle. The lockfile on
my 6.2 installation matches yours, with -icanon present. It looks
as if I misformatted the printcap file. The first few lines looked
like this originally:

lp|ps:\
:br#9600:lp=/dev/ttyd0:mx#0:sf:sh:rw:sb:\
:fc#0177777:fs#003:ms=\
-icanon,-isig,-iexten,-echo,-echoe,-echok,-echoke,-echonl,\

Adding an extra -icanon on the line with ms=, like this:

lp|ps:\
:br#9600:lp=/dev/ttyd0:mx#0:sf:sh:rw:sb:\
:fc#0177777:fs#003:ms=-icanon,\
-icanon,-isig,-iexten,-echo,-echoe,-echok,-echoke,-echonl,\

seems to have cleared up the problem.

Just why the fix worked isn't very clear to me, but I'm very glad it
_did_ work. I suppose this has to be declared a wetware bug, but I
certainly am surprised by the need for it. The lock is set appropriately,
How the icanon flag got set inappropriately is not at all clear. It
was not tampered with in my initial attempts, which inherited the 5.5
printcap:

ns2# more /etc/printcap
lp|ps:\
:br#9600:lp=/dev/ttyd0:mx#0:sf:sh:rw:sb:\
:fc#0177777:fs#003:ms=ixon,ixoff,-isig,igncr,cstopb,-echok:\
:af=/var/log/psacct:lf=/var/log/pslog:sd=/var/spool/output/pslpd:\
:if=/usr/local/libexec/psif:


Many thanks for patient good counsel!

Well, I would hate for you to give it up and come back here again with
the same question in another six months.:-)

I'd never have paid enough attention to the icanon/-icanon flag significance
if you hadn't pointed it out to me.

Thank you, and I'll try to quit asking naive questions.

bob prohaska

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