Re: [Brother-mfc-devel] parport test code in CVS

[Dmitri K. <dm...@us...>]

Hi Fernando,

Well, device ID should work, this is standard IEEE1284 feature.
It does prove that reverse channel is available and operational.

More importantly the fact that the device has accepted a command
and responded with a list of MFC channels is a good step forward.
It indicates that the device is ready to talk MFC protocol.

BTW what channels did you get back? Can you please
execute "./mfctest /dev/parport0 SCN" and attach the output?
Also what kernel and what parpot / ppdev driver version
are you running? What is in your /proc/sys/dev/parport/parport0/* ?

I can offer a few wild guesses about what might go wrong:

* Your kernel and/or driver version is different and there is a
subtle difference in handling non-blocking read requests.

* Your parport is configured differently in BIOS and/or in Linux
(SPP/EPP/ECP, irq, dma support etc)

* Your parport cable is not IEEE1284 compliant.

* Your device needs to be switched into parallel port mode explicitly,
unplugged from USB, power-cycled or something stupid like that.

* Your computer is just too fast (don't laugh I've seen it happening)

* I misunderstood the protocol completely and my MFC works by
sheer luck.

BTW if anyone out there is reading this and has access to MFC with
parallel port, I appreciate if you can try mfctest program fot yourself and
let us know the results. It is a very simple program, just one file.
It's in the project's CVS.

Regards,
Dmitri


----- Original Message -----
From: "Fernando Trias" <ft...@pe...>
To: "Dmitri Katchalov" <dm...@us...>;
<bro...@li...>
Sent: Saturday, 5 April 2003 7:29
Subject: RE: [Brother-mfc-devel] parport test code in CVS


Neither the mfctest.c program not the code snippet I sent earlier to
this list seem to work on my MFC-6800. I get the channels fine, the
send_* functions succeed and nothing is returned by the printer.

I did try some code (below) to get the printer's identifier and it
works, so the printer seems to be able to talk back.

[snip]