Re: lpr problems in 2.0->2.1?

chip@atlantic.net
Sun, 8 Feb 1998 15:57:14 -0500 (EST)

According to Tim Waugh:
> On Sun, 8 Feb 1998 chip@atlantic.net wrote:
> > It's almost as if the lp driver is returning after partial writes when
> > it never used to, and the lprng daemon isn't prepared for it, so it's
> > writing the same data over and over.
>
> That's *strange*! If this is easily reproducible, could you try
> "strace"ing the lprng daemon and any child processes it has to see
> what exactly is going on?

I think I've figured out the three-times-repeated problem.

The default value of lprng's config parameter "send_try" is three.
And I changed my lpr filter recently, adding a program that calls
tcdrain(1); apparently that's not legal on parallel port devices, so
that program exited with failure, which led lpd to think that the
filter had failed and that it should try again.

I've eliminated the drain program from the filter and I'm not getting
repetition any more. But I wonder what could have caused the corruption
that led me to introduce the drain program in the first place. I've
just change to using an interrupt instead of polling; maybe I should put
it back to polling to see if anything changes.

-- 
Chip Salzenberg               - a.k.a. -                <chip@pobox.com>
         "Nice shooting, Zanthar!"  "Thanks, Denise."  // MST3K
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