[sane-devel] CanoScan LiDE 220 works, but only with debug enabled

[Michael Shigorin]

On Mon, Apr 06, 2015 at 02:15:27PM +0200, Stef wrote:
> >I tried turning on debug to find out what is happening and found that
> >everything works perfectly if I enable massive debugging:
> Since the usual way to find out bug is to enable debug traces,
> it is going to be difficult to solve your problem.

Might be race condition if enabling debug changes timings a bit;
in that case putting some load on *all* CPU cores (like make -j
upon something large or enough yes(1) processes stuck into
/dev/null) might change timings over the same margin; but that's
about reproducing "with debug" shift, not about debugging without
masking the problem.

If /tmp is *not* tmpfs it might be worth checking if writing to
tmpfs and not to disk is enough to avoid triggering behaviour
change.

Sorry if that's banal, been debuggin' a similar thing recently...

PS: somewhat interested in LiDE 220 too but no hardware handy yet.

-- 
 ---- WBR, Michael Shigorin / http://altlinux.org
  ------ http://opennet.ru / http://anna-news.info