LPT interruptstorm

Daniel O'Connor doconnor at gsoft.com.au
Mon Aug 2 21:29:07 PDT 2004

Hash: SHA1

On Mon, 2 Aug 2004 21:19, Ian FREISLICH wrote:
> suggested 'lptcontrol -e', but every time I've tried that (even
> with lpd stopped) I get 'lptcontrol: open: Device busy'.  I'm not
> sure what keeps the printer port open other than lpd.

For some reason you can't open /dev/lpt* when something isn't driving the BUSY 
line on the parallel port :(

Actually I just read the code some more :)
You could try

lptcontrol -d /dev/lpt0.ctl -X

lpt0.ctl has the bypass flag (0x80) set in the minor number which prevents 
lptopen() from trying to talk to the hardware (see

I think lptcontrol could do with this diff (attached)

- -- 
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
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