Re: [PARPORT] Re: parport scanners and the 90c26 adapter

Michele Bini (mibin@tin.it)
Sat, 8 May 1999 16:44:28 +0000

On Fri, May 07, 1999 at 04:41:56PM -0400, grant@torque.net wrote:
> > Who is working on it?

> I am, with some help from a small number of testers.

Glad to hear that. You can count on me as a tester, if
you like. I assume the responsibility of any eventual
damage.

> Currently, the driver is stable for all devices _except_
> scanners. We can make it work with scanners, but it
> is extremely slow. So slow that it is not useable.

That's better then no support at all.

> I have not yet solved this problem.
>
> > I'd like to work on the code produced so far,
> > even if it is still at an experimental stage.

For working I mostly meant testing or tuning.

> Perhaps. Have you done any device driver debugging before ?

Not much, however i have some experience of port i/o with
assembler and i know the basics about kernel modules and
kernel patching (once i sent at linux-kernel a patch to
make kernel nfsroot over plip possible, but it got few
attention).

I am pleased that a skilled person like you is developing
this chip's support, and i am very probably unable to
replace you on this task.
The point was that i wrongly feared that
nobody was anymore developing on it.

> Do you understand the risks ? Be sure that you have a machine
> available with nothing important on it.

Do you mean the risks linked to the scanner (i heard about
overheating, but it seems rare and specific to some models)
or generic kernel patching/hacking risks (like fs corruption)?
I am aware of the latter, and assume the responsibility
of eventual damage (even regarding scanner).

> > I received a Phantom 336CX scanner as a present
> > from a friend, and it seems to have a 90c26
> > parallel-scsi adapter in it.
>
> > Using the paride on26 module i'm currently able to
> > turn off and on the led on it, and the driver seems
> > to be able to talk to the chip at first, but after
> > a few seconds it timeouts giving
> >
> > on26: Device reset failed (ff,ff)
>
> Actually, what's happened is that the paride driver
> detects the 90c26 chip. The registers in the chip have
> entirely different functions in the IDE application and
> the SCSI application, except for the bus reset bit. The
> ISA device reset and the SCSI bus reset happen to be
> controlled by the same bit in the same register. That's
> why you see the light flash.

Thank you. Is there any spec on this chip?
I haven't found any spec on OnSpec's site (ironically).

-Michele

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