Re: [PARPORT] bidirectional paraport driver??
Mon, 21 Sep 98 10:59:00 +0200

Hi Jussi!

> Does anyone know where I could find a driver for bidirectional parallel
> port? I've tried to find it everywhere but with no luck at all...
What do you understand "a driver for bidirectional parallel port"?
Are you looking for some parport functions, negotiating "IEEE1284 byte mode"
and getting data in "byte mode"?

If so, I have good news for you:
We discussed some months ago here a generic IEEE1284 support for the
parport code. Some people posted some demands, this IEEE1284 support
should fullfill (e.g. there is an autoprobing for available IEEE1284
modes at the device, but a driver using this generic IEEE1284 support
should be able to overwrite this autoprobing, if it knows, that its
device is capable for more than responsed modes while probed; e.g. this
IEEE1284 support should optionally work atomically, i.e. doesn't use
schedule, but returns and uses task queues for being rescheduled; and lot
of more). I started to write this code, but then hadn't much time.

Now the news: I worked a lot duing the last days and probably will finish
this IEEE1284 support this week. I hope it will be possible to add this code
to the frozen 2.1-kernel. Therefore I did the following: The new autoprobe
code only will be called, if you uncomment a certain define line in
parport_probe.c. If you don't uncomment this line, you have only
new functions in parport_ieee1284.c, but no modified function


P.S. Among those new functions inside parport_ieee1284.c there is a
function called "parport_ieee1284_read_block", which reads data from
a device via the "hightest" available IEEE1284 mode, which was determined
while autoprobing or was overwritten by software. If necessary an
IEEE1284 negotiation is performed first. In your (Jussi Pajala) case
the hightes available IEEE1284 reverse mode is probably byte mode.

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