Re: Printing to off-line printer in 2.4.0-prerelease

Peter Osterlund (peter.osterlund@mailbox.swipnet.se)
Thu, 4 Jan 2001 02:09:56 +0100 (CET)


On Thu, 4 Jan 2001, Andrea Arcangeli wrote:

: I'm worried somebody needed to disable LP_CAREFUL to print, probably
: it's not a big deal to keep it.

I removed it because otherwise I would have had to do twice as many tests
to convince myself that all combinations of flags and printer states
worked correctly. I can reinsert it if you think that's necessary. But
then I don't think the tunelp man page and the comments in the kernel
should say that it is obsolete. I think obsolete means "you should never
ever have to use this stuff".

: However parport_write can still could silenty discard data, but maybe
: it can't notice errors with some handshake.

At least with my printer, it only discards data when it is powered off. If
you power off the printer between the times when lp_wait_ready returns and
parport_write is called, I think it is ok to lose data. After all, if the
power off had occurred a few ms later, the data would already have been in
the printer when it was powered off, and then you would have lost data
anyway.

: I didn't checked the details of the DMA based handshake so Tim needs
: to comment if this can be considered a final/right fix (I hope it's
: not ;).

I don't understand the lowlevel parport details, so I can not comment on
this.

-- 
Peter Österlund             peter.osterlund@mailbox.swipnet.se
Sköndalsvägen 35            http://home1.swipnet.se/~w-15919
S-128 66 Sköndal            +46 8 942647
Sweden

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