Re: udev and parallel port support

[Sergey Vlasov <vsu@altlinux.ru>]

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On Tue, 4 Oct 2005 17:14:11 -0500 Jason Dravet wrote:

> Thank you for the response.  I realize that some devices need static nodes,
> but I am wondering why parallel ports fall into this category at least they
> do according to redhat anyways?

Actually, the lowlevel port driver (parport_pc, or maybe something
other like parport_serial) can in many cases be loaded automatically
(on most modern machines the presence of a legacy parallel port is
shown by PnP or ACPI).  Only old hardware which does not support any
form of PnP will require manual loading of parport_pc.

The real problem is that currently there is nothing which will trigger
loading of the highlevel driver (lp or ppdev).  With recent hardware
it is possible to find out what is connected to the parallel port
(look at /proc/sys/dev/parport/parport0/autoprobe), but this is often
unreliable.  So the easy way is to create static nodes for /dev/lp*
and /dev/parport*, and then a program which tries to use these devices
will trigger loading of the appropriate module.

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