Just in case someone else runs into this problem, I briefly summarize the
problem, attempts to solve the problem and the ultimate solution.
The last item first: I gave up! Short of becoming a kernel hacker, there is
no way to get the parallel port going. Luckily my printer (an Epson SP 820)
also has an USB port: connecting the printer via USB works fine. Case closed.
The problem:
* The Compaq Presario 5008US pc uses the Standard Microsystems Corp.
LPC47U332 chip (identified via motherboard inspection and correctly
located by Gunther Mayer's "lssuperio" program). The hardware is fine
as shown by booting windows.
* The BIOS configures this chip correctly (parallel port enabled and healthy)
* Very early during the SuSE 8.0 boot process, the parallel port is
disabled. The older version 7.2 did not do this (same machine / hardware).
* prarport_pc subsequently fails to detect the parallel port.
* The pc is otherwise fully functional, including the other devices that
the superio chip facilitates.
Attempts to enable the parallel port at a later stage before installing
parport_pc failed. I programed all the parallel pc parameters, verified that
the power management did not turn of the parallel port, verified that the
floppy controller does not borrow pins from the parallel port, etc.
The registers read-out the correct values after this. The chip identifies
itself just as the manual (courtesy of Gunther Mayer) states.
Just to be really sure that I'm talking
the the right chip, I verified that the reserved 0-bits in certain registers
really stay stuck at 0 (they do). There are some hints in the chip manual that
not all parport configuration changes are possible, for example you need to set
it to plain parallel out-mode before transition into ECP. I followed that too.
I guess that it is possible to wedge the parallel port into an undefined state
where just changing the configuration will not resurrect it. In any event,
nothing worked. The last resort would have been to software-reset the chip,
but that would hang up the keyboard, loose the interrupt controller and cause
all sorts of havoc, so I didn't do that.
The bug is NOT in the parport software: by the time it is run, the
parallel port has been turned off already. SuSE provides the kernel sources,
but I don't have the time and knowledge to dive into that. Their installation
support does not cover the parallel port.
Many thanks for all the friendly and helpful suggestions I received in this
forum.
Kind regards,
-- A. Nowatzyk
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This archive was generated by hypermail 2b29 : Fri Jul 19 2002 - 21:36:46 EDT