Subject: Re: delayed transactions
To: None <>
From: Thomas Michael Wanka <>
List: port-i386
Date: 02/01/2001 14:38:46
On 1 Feb 2001, at 13:47, wrote:

> what's this BIOS option doing?
> when i have it set netbsd could (rarely) lock up and then reboot on
> larger system load (2 compilations+X+ disk ops is enough)

AFAIK at least every chipset ond probably every motherboard 
manufacturer has his own definition of such options.

The Asus P5A-B and K7M (P2B does not seem to have that option) 
manual says:

"If Enabled, it frees the PCI Bus during CPU accessing of 8-bit ISA 
cards which normally consume about 50-60 PCI Clocks without PCI 
delayed transaction. If PCI Bus Masters cannot use the PCI Bus, 
leave this on the default setting of Disabled for ISA cards that are 
not PCI 2.1 compliant."

If I understand that correctly, if your ISA and PCI cards go well 
together, you can get performance enhancements if you enable this. 
If the ISA and PCI cards do not get along and you enable this 
option, while an ISA card is accessing the CPU, PCI cards could be 
blocked and errors can occur.