From owner-aic7xxx  Wed Jan 14 10:45:44 1998
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Date: Wed, 14 Jan 1998 19:44:56 +0100
To: aic7xxx@FreeBSD.ORG
From: Prischl Roman <roman@freebee.tu-graz.ac.at>
Subject: Linux AHA-2940AU & Zip Plus problem (2.1.78)
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Hello!

It seems that I got troubles with the 2.1.78 Linux-Kernel.

Everything starts to load right....
When I try to copy some file(s) (actually more MBytes) after a few seconds
there are messages which tell 

"(scsi0:5:0) Underflow - Wanted at least xxxxx, got yyyyy, residual SG
count 1" 

and 

"(scsi0:5:0) Data Overrun of xxxxx bytes detected in Data-Out phase, tag 0;
forcing a retry"

This happens a few times and then the scsi-system stops working. Both LEDs
(Zip & Hostadapter) keep ON (not flickering as under normal transfers) and
there's no further transfer.
The only way to get out of this situation is to do a hardreset.

I tried every option (Linux: QueueTagging ON/OFF, SCB ON/OFF, AHA-2940AU
BIOS: Enable/Disable Disconnect) I saw....

Under Linux 2.0.32 there are no problems with this configuration (as there
aren't in Win95 *shame* too...).

My hardware is
	i586
	AHA-2940AU (Only extern devices, therefore manual termination enabled)
	HP Scanjet 4p
	Iomega Zip Plus Drive

I compiled the 2.1.78 kernel with scsi-core in kernel and sd_mod,sg and
aic7xxx as modules (kerneld). 

Thankx for your hints...

Roman