Re: [PARPORT] ECP mode for printers

David Campbell (
Thu, 17 Jun 1999 06:54:58 +0800

To: "David Campbell" <>
Copies to:
Subject: Re: [PARPORT] ECP mode for printers
Date sent: Wed, 16 Jun 1999 08:58:31 +0100
From: Philip Blundell <>

> >The problem is that certain device drivers require access to the
> >parallel port within several seconds or result in a kernel OOPS. If
> That isn't really acceptable anyway. Is it really not possible to write the
> driver in such a way that it doesn't crash?

*smoke rising* - Phil, I thought you knew the answer to this one.

The "problem" is the mid-level SCSI layer which jumps up and down on
the ZIP driver. You can not prempt the lp driver when there is data
in the FIFO since you will loose upto 16 bytes. HP laserjet printers
generate screwy printouts if they miss a byte in a graphics stream.

Also the mid-level SCSI does not know how to handle a cable break
properly (or it is very vaugely documented).

David Campbell
"This is not an office, rather Hell with fluorescent lighting"

-- To unsubscribe, send mail to: --
-- with the single word "unsubscribe" in the body of the message. --

This archive was generated by hypermail 2.0b3 on Wed 16 Jun 1999 - 18:56:49 EDT