RE: Talking to parallel port in 2.6 kernel without using parport

[Kathy Frazier]

Alan,

That was a problem!  The lp driver was already loaded.  If I remove it and
then load my driver, it returns with success from parport_register_device.
Thanks for your help!

Regards,
Kathy

-----Original Message-----
From: Alan Cox [mailto:alan@xxxxxxxxxxxxxxxxxxx] 
Sent: Friday, April 25, 2008 1:12 PM
To: Kathy Frazier
Cc: 'Kathy Frazier'; linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: Talking to parallel port in 2.6 kernel without using parport

> One of our engineers downloaded source code a while back from 
> linux-2.6.18-rc7, but I am not sure how close that is to what is 
> installed on my system (uname -r returns 2.6.18-1.2798.fc6.  When I 
> set my printk to 8 (echo 8 > /proc/sys/kernel/printk), there are no 
> messages shown on the failure.  According to the source code I have, 
> the only silent failure in parport_register_device is:

Nothing immediately strikes me.

> When I change the flags from PARPORT_FLAG_EXCL to 0 in the call to 
> parport_register_device, the call returns a non-zero to indicate success.

Do you have the printer driver loaded already ? (and does it behave if you
do rmmod lp first)

> Can you tell me what I am missing?  Where can I get the actual source 
> code that goes with this version to further unravel this?

>From the .fc6 it would be an old Fedora kernel so very close to standard
2.6.18 from kernel.org, but the Fedora Core kernels are available from the
Fedora download pages - the .srpm package for each kernel is the one
matching the same binary - so google for "2.6.18-1.2798.fc6.src.rpm"

http://www.mjmwired.net/resources/mjm-fedora-fc6.html has a few notes on it.


To be honest this area of the kernel hasn't changed much over recent times.
Let me know if you can't figure out what is going on.

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