On Friday, January 28, 2011 03:10:50 pm Kirk Wallace did opine:
> On Fri, 2011-01-28 at 11:18 -0600, Jon Elson wrote:
> > Mark Wendt wrote:
> > > Really makes one wonder how any of this stuff works at all. You
> > > gotta love it. A standard with no real standards... ;-)
> >
> > Yes, completely appalling, and I have to keep hopping to make my
> > boards work with a wide variety of par port chips. What a nightmare!
> > I think I finally have all of my boards set up so that if they don't
> > work with any particular parallel port, I can pretty honestly say
> > "It's not MY fault!" It is totally amazing to me that these chips
> > can't even follow the LOOSE standard laid out in those docs, which
> > just kind of show this signal comes before that one.
> >
> > Jon
>
> I'm beginning to think that maybe the most popular chip, maybe Moschip
> 9815, should be considered the standard, then make it work on that. The
> Lava and Siig cards may be better, but the Moschips are easy to find and
> cheap.
Based on the estimate that at least 95% of these aftermarket cards are
based on this MosChip 9815, could an insmod-able kernel driver could be
written that would make it work?
If this could be done, it sure seems like as close as we can get to a one
size (nearly) fits all scenario. I think that of course would have to be
subject to how many motherboard's 0X378 ports would be broken. Possibly
with some mechanism to insmod the correct, MosChip 9815 compatible driver
if it is going to be used. I just looked at the linux drivers, and while
they detect this netmos 9815 chipset, the quirks handling seems more
generic, mostly via lookup tables. An lspci -nnvv of my card:
00:0a.0 Communication controller [0780]: NetMos Technology PCI 9815 Multi-
I/O Controller [9710:9815] (rev 01)
Subsystem: LSI Logic / Symbios Logic Device [1000:0020]
Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR- FastB2B- DisINTx-
Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort-
<TAbort- <MAbort- >SERR- <PERR- INTx-
Interrupt: pin A routed to IRQ 11
Region 0: I/O ports at a000 [size=8]
Region 1: I/O ports at a400 [size=8]
Region 2: I/O ports at a800 [size=8]
Region 3: I/O ports at ac00 [size=8]
Region 4: I/O ports at b000 [size=8]
Region 5: I/O ports at b400 [size=16]
Kernel driver in use: parport_pc
Kernel modules: parport_pc
But this, to my untrained eye, gives me no clues as to the available
support modes. From my presently running 2.6.37 kernel tree on this box,
TODO-parport:
===
Things to be done.
0. Fix the bugs (see BUGS-parport).
1. Proper documentation.
2. A better lp.c:
a) ECP support would be nice. This can only work if both the port and
the printer support it.
b) Handle status readback automatically. IEEE1284 printers can post
status
bits when they have something to say. We should read out and deal
with (maybe just log) whatever the printer wants to tell the world.
3. Support more hardware (eg m68k, Sun bpp).
4. A better PLIP (make use of bidirectional/ECP/EPP ports).
See <URL:http://people.redhat.com/twaugh/parport/>.
===
BUGS-Parport:
Currently known (or at least suspected) bugs in parport:
o lp doesn't allow you to read status while printing is in progress (is
this still true?).
o parport_pc_ecp_read_block_pio() is broken. parport will revert to the
software-driven mode in ieee1284_ops.c
See <URL:http://people.redhat.com/twaugh/parport/>.
===
So apparently Tim Waugh is aware there are problems. But I am not the one
to give him a nudge as we've had very strong words in the past over
fedora's non-inclusion of gutenprint into fedora, 5 years after gimp-print
had been declared obsolete and unsupported. Just one of the reasons I no
longer run fedora here on this box, now its pclos, and generally pretty
upto date and sweet running. My kde is now at 4.5.6 for instance, and
since 4.6 was released yesterday, I expect that to show up in the pclos
repos in another week.
> BTW, the attached has been fun to look at parallel port registers.
> (Caution, can cause harm to your PC if you plug in the wrong address)
Saved. Thanks.
--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
<http://tinyurl.com/ddg5bz>
Anoint, v.:
To grease a king or other great functionary already sufficiently
slippery.
-- Ambrose Bierce, "The Devil's Dictionary"
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