Re: [PARPORT] Re: IEEE 1284 development

Nicolas Souchu (
Fri, 11 Dec 1998 23:12:52 +0000

On Wed, Dec 09, 1998 at 10:00:18PM +0100, Andrea Arcangeli wrote:
>On Wed, 9 Dec 1998, Nicolas Souchu wrote:
>>Couldn't the IEEE1284.3 standard be implemented as a regular driver? It
>Hmm, for the idea I have of IEEE1284.3 no, there are many issues for every
>compliant pardevice (with irqs and other things). But I have not read it
>in details and I have only an old draft of IEEE1284.3 to read so I could
>be wrong here :(.

So, if you consider devices are not totally compliant, which is mostly
the case I believe, how to you adapt your parport stack? If you
give a more thin granularity to your interfaces, you can change your stack
for device particularities.

Anyway, parallel port problems will disappear with USB. A good point for
users, unemployment for developers :)

>>would just share the port with others, at least with drivers that
>>operate with the terminal peripheral of the daisy chain.
>My point is exactly the daisy chain. Right now it' s the pardevice that
>handle the switch considering all other devices as legacy devices. This
>works fine because we do all in software and we don' t care at all about
>IEEE or legacy devices. If you want to take advantage of the irq chaining
>of IEEE1284.3 instead we should do something of more high level in parport
That's what I was suggesting.

>I think... This is a bit sad, since parport scheduling is perfect right
>now and will instead need to change it. For IEEE1284 the change seems
>right and good though. For 1284.3 it' s more tricky.

Right, and each time you add improvments to parport you break the toy.
That's why I've choosen to implement 1284 support at the top of the existing
ppbus stack.

>Andrea Arcangeli

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