Subject: question about the isa bus speed controller on I386 platform.
To: None <tech-kern@NetBSD.ORG>
From: Brian Buhrow <email@example.com>
Date: 03/20/1997 14:55:16
Hello I386 gurus. I have a question about the timing controllers on the
ISA bus and how NetBSD handles them.
Here's my problem. I have a hardware speech device which sniffs on the ISA
bus and copies data destined for the display adapter into its own memory
for conversion to speech. Under NetBSD 1.0 and earlier, this device works
fine. Some time after 1.0 was released, soething changed about the way
NetBSD sets the timing controllers on the ISA bus such that this device
becomes very sluggish. I suspect either the bus rate itself or perhaps one
of the refresh timers for the display adapter.
Does anyone know of specific changes that were made in the way
NetBSD drives the ISA bus that were made either to correct for some defect
or to improve performance which might have this effect? I'm sorry I can't
be more specific about which lines the device uses to gain its timing
signal from the bus, but I haven't had time to dig down into the almost
lost lore of the engineering details of this beast.
Any ideas on what I should look at or where I might ask would be