Re: PLIP gives me funny errors

[hosler@lugs.org.sg (Greg Hosler)]

Hi,

I have no real experience w/ plip, but a few possible guesses.

> 	I'm trying to get PLIP working between my IBM TP701C and my PC.
> 	I cannot get it to work properly. I followed the PLIP mini-howto 
> to the last step and it fails. On my PC, I get the following (yes its 
> double) when I typed "ifconfig plip2 200.0.0.2 pointopoint 200.0.0.1 up"
> 
> SIOCSIFFLAGS: Try again
> SIOCSIFFLAGS: Try again

is the ifconfig being done by the "root" user ? -- if it's in the "rc" files,
then yes it is. if you're manually doing it, are you "root" when you do the
ifconfig. if not, you probably want to retry the ifconfig as root.

> The funny thing is, on my PC the plip devices start from plip1 -> plip2 
> (on my notebook it's from plip0 to plip 1) [2 lpt ports on each machine]
> My PC runs linux kernal 1.2.13 and my IBM runs kernal 1.3.30

The different numbering may be due to whether you have the printer module
(lp.c) loaded, or not. if you do, then that will shift the device numbering.

also....

recall that the 1.3.x kernels were developmental kernels. in many of them
one thing, or another, was borke. While they are ok to do testing with,
as long as they work for you, then fine, but the minute you start having
problems (such as you are describing), then the appropriate action is to
switch kernels. either go back to 1.2.13, or go forward to 2.0 (minimally
2.0.0) -- There were 70 or more patchs between the 1.3.30 kernel and the
official 2.0 kernel -- many of these were serious patches, affecting either
various drivers, or other subsystems, including the network code. I definately
remember networking problems on a number of the 1.3.x kernels. might be that
you're banging your head against one here...

> 	Any idea ?
> 	And is it true some notebooks cannon run plip becoz of the way 
> the parralel ports are used ? (Something in the howto about control signals)

I just diff'd the plip.c module between a 1.2.13 source tree and a v2.0
source tree, and there are a number of differences between the 2 plip
drivers (i.e. from 1.2.13, to 2.0). One set of diff's are due to the 
modularization of the kernel. another set appear to be network related 
(the networking code was very much rehashed/rewritten during 1.3, affecting
most networking stuff...) I do NOT suspect an issue w/ the EPP printer port
(EPP == Enhanced Printer Port) on the laptop.

In short, your course of action is probably to upgrade the laptop to a more
stable kernel, either 1.2.13, or 2.0

Finally, the cable should be "a de facto standard parallel null cable -- sold
as a "LapLink" cable by various places" (from plip.c -- there are also 
instructions for making one yourself, though a LapLink cable ought to be
available from CableTronics, possibly SunTronics, possibly other stores).

However, I do not think the cabling is at the heart of your SIOCSIFFLAGS error. the
ifconfig _probably_ doesn't care whether the cable is plugged in, or not.

not sure if any of the above will help, or not...

regards,

-Greg