David Campbell (campbell@gear.torque.net)
Sat, 17 Jan 1998 08:06:43 +0000
> Date: Fri, 16 Jan 1998 21:20:05 +0000 (GMT)
> From: Riley Williams <rhw@bigfoot.com>
> To: David Campbell <campbell@gear.torque.net>
> Cc: linux-parport@torque.net
> Subject: Re: [PARPORT] IOmega driver bug
> Hi David.
>
> On Mon, 12 Jan 1998, David Campbell wrote:
>
> ===8<===CUT===>8===
>
> >> The above-mentioned friend is quite happily using the same drivers
> >> (indeed, the same kernel - we transferred his kernel image to my
> >> machine and rebooted under it with no change in the situation),
> >> and gets no problems in EPP mode, which makes me suspect there's
> >> more than one EPP chipset, and mine is one the current driver
> >> doesn't handle correctly.
>
> > See .sig below for my comments on parallel port chipsets.
>
> > A quick fix is to find the line in ppa.h where it does:
>
> > ============================
> > #ifndef CONFIG_SCSI_PPA_HAVE_PEDANTIC
> > #define CONFIG_SCSI_PPA_HAVE_PEDANTIC 3
> > #endif
> > ============================
>
> > and change it to
>
> > ============================
> > #undef CONFIG_SCSI_PPA_HAVE_PEDANTIC
> > #define CONFIG_SCSI_PPA_HAVE_PEDANTIC 4
> > ============================
>
> > There are some PCI/ISA chipsets which do not support word (4
> > byte wide) writes to the ISA bus and cause all sorts of timing
> > issues. This affects approx 5% of the people out there but the
> > improvement when it works is approx +50% transfer rate.
>
> I've tried it with that tweak, and no difference to its behaviour.
>
> Also out of curiosity, I looked through the sources to find out
> what differences that tweak would make to the code - and found no
> differences whatsoever. It was simple to show that the previous
> value was 3 and equally simple to discover that the only usage of
> that item was in #if statements which differentiated three cases:
> (a) value of 0, (b) value of 1 and (c) value greater than 2. As a
> result, both the values of 3 as current and 4 as suggested
> resulted in the same code.
>
> Curiosity prompts me to ask whether there should be a meaning to a
> value of 2 ???
I will have to check the code, could you send me a copy of the "dmesg"
output after the driver has failed to load. At the moment I am guessing
what is happening here...
David Campbell
=======================================================
campbell@torque.net (Parallel port device related mail)
dcampbel@p01.as17.honeywell.com.au (For all other mail)
Just when you thought you have seen every possible
parallel port chipset there is, some manufacturer comes
out with a new quirk. Just to make things worse, every
mainboard manufacturer on the planet decides to use it.
-- To unsubscribe, send mail to: linux-parport-request@torque.net --
-- with the single word "unsubscribe" in the body of the message. --
This archive was generated by hypermail 2.0b3 on Wed 30 Dec 1998 - 10:17:20 EST