Re: [PARPORT] ECP mode for printers


David Campbell (campbell@gear.torque.net)
Wed, 16 Jun 1999 07:32:18 +0800


Send reply to: "Dusan Vujosevic" <DusanV@cadlink.com>
From: "Dusan Vujosevic" <DusanV@cadlink.com>
To: "parport mailing list" <linux-parport@torque.net>,
               "David Campbell" <campbell@gear.torque.net>
Subject: Re: [PARPORT] ECP mode for printers
Date sent: Tue, 15 Jun 1999 17:54:03 -0400
Organization: CADlink Technology

> Thanks for your info. I'd still like to try that ECP driver if you can point
> me to it. Are you saying that these drivers are slow as hell? Are there any
> plans for new ones?

I am sure someone coded one, I will toss one together in a free
moment but you will have to test it yourself. You may have to break
out mknod for creating the devices.

The problem is that certain device drivers require access to the
parallel port within several seconds or result in a kernel OOPS. If
the printer buffer was to fill there will still be data in the FIFO
which can not be recovered, if the stall was to take longer than 3
seconds (a page eject on a 4 ppm laser) then the kernel would fall
over.

It is not the parallel port hardware that is the problem but the
printer on the other end - there is no standard flow control method
which allows us to peer and say "we can transfer another 10kB without
problems", if we could do that then we would not have the current
headaches.

David Campbell
=======================================================
campbell@torque.net
"This is not an office, rather Hell with fluorescent lighting"

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This archive was generated by hypermail 2.0b3 on Tue 15 Jun 1999 - 19:35:36 EDT