Re: [PARPORT] RE: [patch] ieee1284 nibble mode

Tim Waugh (
Sun, 24 Jan 1999 13:08:23 +0000 (GMT)

On Fri, 22 Jan 1999, Harald Koerfgen wrote:

> According to an old Powerpoint presentation I found on HP's web site
> the first two bytes of the device id string describe the length of it.
> I tried that with my 5500W and it works fine. Andrea, I do have user
> space test program available which reads the device id of my printer
> in NIBBLE and ECP mode and you may want to try this with your Epson
> Stylus. I'll send the program to you when I'm back home, if you like.

That is a good point. The standard actually says that we shouldn't read
more than advertised in the first two bytes.

I've updated my 1284 patch (patch-2.2.0-pre9-1284) so that it does this.
The change is in pnp/parport_probe.c

That still leaves the problem that the nibble read might return early
because of a dud data-ready indication. Andrea, you might want to
instrument the nibble read function so that it displays the status
register each time round the loop. They _must_ do _something_ different
when we reach the end.


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This archive was generated by hypermail 2.0b3 on Sun 24 Jan 1999 - 08:25:53 EST