Re: parallel port printing

[Ron Johnson <ron.l.johnson@cox.net>]

On Wed, 2002-08-07 at 11:22, Wayne Topa wrote:
> Ron Johnson(ron.l.johnson@cox.net) is reported to have said:
> > On Tue, 2002-08-06 at 09:53, Mark Roach wrote:
> > > On Mon, 2002-08-05 at 18:30, Ron Johnson wrote:
> > > > Hi,
> > > > 
> > > > Here's the relevant (I think) output from /var/log/dmesg:
> > > >    parport0: PC-style at 0x378 (0x778) [PCSPP,TRISTATE]
> > > >    parport0: Printer, EPSON Stylus C80
> > > >    parport_pc: Via 686A parallel port: io=0x378
> > > >    lp0: using parport0 (polling).
> > > > and /etc/modules:
> > > >    parport
> > > >    parport_pc
> > > >    options parport_pc io=0x378 irq=7
> > > >    lp
> > > 
> > > I don't believe module options belong in the modules file. All that
> > > happens with that file is that each line gets modprobed by the modutils
> > > initscript. I would start by putting the options line in a file in
> > > /etc/modutils/ and running update-modules which will put merge your file
> > > into /etc/modules.conf
> > 
> > Thanks.  Is there a more comprehensive doc on update-modules and
> > /etc/modutils?  I.e., which file to I put the options in?  The
> > update-modules man page is pretty skimpy.
> > 
> > Also:
> > - why wouldn't the kernel be picking up from the hardware that it is 
> > to use IRQ7?  It seems to be able to speak to the EPSON even in polling
> > mode...
> > - must I alias the lp module to /dev/lp0?  The old HOWTO at
> > linuxprinting.org doesn't know whether aliasing lp to /dev/lp0 is
> > only for devfs or not.
> 
> Is there a reason you are using an IRQ for the printer?  It isn't
> required and could be used for something else.

Well, using interrupts is more efficient than polling ports.
Since kernel 2.2 (or maybe 2.0) linux has allowed irq sharing
(as long as each device has a distinct io port!).

> I haven't used IRQ7 for the printer in 7-8 years as I use it for
> multi-port serial cards instead. I disable the printer in the bios
> and put this in lilo.conf.
> append = "lp=parport0 parport=0x378,none"

Thanks!

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| Ron Johnson, Jr.        Home: ron.l.johnson@cox.net           |
| Jefferson, LA  USA                                            |
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