Re: [PATCH WIP] parport: add device model

From: Ondrej Zary
Date: Fri Apr 10 2015 - 14:30:15 EST

On Friday 10 April 2015 16:30:38 Sudip Mukherjee wrote:
> This is work-in-progree, not for applying to any tree. Posting now for
> your comments so that I know if I am in the proper track.
> in parport_register_driver() driver is registered but i am not linking
> anywhere the device with the driver, but yet when I am testing this
> patch I am seeing in sys tree that parport0 is linked with
> the lp driver. Is it done in the device core? I am missing this step
> somewhere.
> In parport_claim() the attach is unchecked as of now, I think we will
> need my initial patch series of monitoring the attach return value along
> with it.
> while testing I am getting NULL dereference with daisy.c, and after
> disabling PARPORT_1284 , I am getting some new errors. so if you are
> testing this patch please keep in mind that still lots of work is
> pending.
> My main intention to post it now is to know if my approach is correct.

Many newer parallel port devices support plug&play (IEEE1284 device ID) but
Linux never supported it properly. The ID is probed and even the class is
printed in the kernel log (drivers/parport/probe.c) but there's no support
for module autoloading based on that.
This could be a good opportunity to add this support. I was thinking about
this while playing with some parport webcams recently.

Ondrej Zary
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