Re: Multi-function PCI devices

[Michael Reinelt <reinelt@eunet.at>]

Gérard Roudier wrote:
> 
> > Tim Waugh wrote:
> > > > Adding PCI entries to both serial.c and parport_pc.c was that easy....
> > >
> > > And that's how it should be, IMHO.  There needs to be provision for
> > > more than one driver to be able to talk to any given PCI device.
> >
> > True, true, true.
> 
> Could you start up your brain now :) 
There's no need to start it. My brain is either 'always on', or
'suspended to ram' :-)

> and think about the actual issue. All
> the drivers must share the device resources and there is no (simple) way
> to do so generically.
> What you want to do is to write a single software driver, optionnaly
> broken into several modules, that is aware of all the functionnalities of
> the board and that will register to all involved sub-systems as needed.

I agree. that would be the clean solution. Jeff Grazik provided some
sample code, I'll try to write a driver according to this. If I find the
time....

But what I want to know before I spend time (and not-earning-money :-)
into this, I want to know: Is this the right way (TM)? How do other
multiport cards deal with this issue?

This is a specific question to the serial and parallel maintainers: are
there cards supported by _both_ the serial and parallel subsystem? Do
they work with 2.4.3? Will they work in the future? (I'm too lazy to
compare the PCI tables from serial and parallel ;-)

Another (design) question: How will such a driver/module deal with
autodetection and/or devfs? I don't like to specify 'alias /dev/tts/4
netmos', because thats pure junk to me. What about pci hotplugging?

(keep in mind that I'm new to kernel development)


> What about the option of using a different hardware ? :-)

Har har har. Could you please tell me where to get one? I don't know how
it's in your country, but here in austria you can call yourself a lucky
guy if you even find a PCI serial/parallel card. If you find one, you'll
find _one_. It's packaged in a little box where it reads "PCI 2S/1P
board". The 'manual' is a bit larger than a stamp. 

I could buy one after another, and try if they have a well-designed PCI
interface. 

I don't have the time for this.

I agree with you that this kind of hardware is junk. But there's a lack
of alternatives....

If there's a reasonable number of 'good' hardware out there, I'll forget
about Netmos and buy me a new card. If not, I'm willing to provide a
driver. 


bye, Michael

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