Re: [PARPORT] IOmega driver bug

Riley Williams (
Fri, 16 Jan 1998 21:20:05 +0000 (GMT)

Hi David.

On Mon, 12 Jan 1998, David Campbell wrote:


>> 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:

> ============================
> #endif
> ============================

> and change it to

> ============================
> ============================

> 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 ???

Best wishes from Riley.

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This archive was generated by hypermail 2.0b3 on Wed 30 Dec 1998 - 10:17:20 EST